Mearsheimer was born in December 1947 in Brooklyn, New York. He was raised in New York City until the age of eight, when his parents moved his family to Croton-on-Hudson, New York, a suburb located in Westchester County.When he was 17, Mearsheimer enlisted in the U.S. Army. After one year as an enlisted member, he chose to attend the United States Military Academy at West Point. He attended West Point from 1966-1970. After graduation, he served for five years as an officer in the U.S. Air Force.

While in the Air Force, Mearsheimer earned a Masters Degree in International Relations from the University of Southern California in 1974. He subsequently entered Cornell University and earned a Ph.D. in government, specifically in international relations, in 1981. From 1978-1979, was a research fellow at the Brookings Institution in Washington, D.C. From 1980-1982, he was a post-doctoral fellow at Harvard University’s Center for International Affairs. During the 1998-1999 academic year, he was the Whitney H. Shepardson Fellow at the Council on Foreign Relations in New York.

Since 1982, Mearsheimer has been a member of the faculty of the Department of Political Science at the University of Chicago. He became an associate professor in 1984, a full professor in 1987, and was appointed the R. Wendell Harrison Distinguished Service Professor in 1996. From 1989-1992, he served as chairman of the department. He also holds a position as a faculty member in the Committee on International Relations graduate program, and is the co-director of the Program on International Security Policy.

Mearsheimer has written extensively about national security policy and international relations theory, especially realism, which he defines as a state’s tendency to attempt to gain as much relative power as possible and eventually become the hegemon of the international system.

Mearsheimer’s books include Conventional Deterrence (1983), which won the Edgar S. Furniss Jr., Book Award, Nuclear Deterrence: Ethics and Strategy (1985), Liddell Hart and the Weight of History (1988), and The Tragedy of Great Power Politics (2001), which won the Joseph Lepgold Book Prize, and The Israel Lobby and U.S. Foreign Policy (2007). He has also written many articles that have appeared in academic journals like International Security, and popular magazines like The London Review of Books. Furthermore he has written a number of op-ed pieces for the New York Times, the Los Angeles Times, and the Chicago Tribune.

Mearsheimer has won a number of teaching awards. He received the Clark Award for Distinguished Teaching when he was a graduate student at Cornell in 1977, and he won the Quantrell Award for Excellence in Undergraduate Teaching at the University of Chicago in 1985. In addition, he was selected as a Phi Beta Kappa Visiting Scholar for the 1993-1994 academic year. In that capacity, he gave a series of talks at eight colleges and universities. In 2003, he was elected to the American Academy of Arts and Sciences.

Mearsheimer has acquired some renown among the University of Chicago community for his colorful language and idiomatic speech in his classes and lectures. He famously refers to the United States as "Uncle Sugar," the Soviet Union as "the Bear;" the action of international politics occurs "all over God's little green acre."

In March 2006, Mearsheimer and Stephen Walt, academic dean and professor of International Relations at the Harvard Kennedy School of Government, published a working paper and an article in the London Review of Books discussing the power of the Israel lobby in shaping US foreign policy. They define the Israel lobby as "a loose coalition of individuals and organizations who actively work to steer US foreign policy in a pro-Israel direction." They emphasize that it is not appropriate to label it a "Jewish lobby", because not all Jews feel a strong attachment to Israel and because some of the individuals and groups who work to foster U.S. support for Israel are not Jewish; according to Mearsheimer and Walt, Christian Zionists play an important role. Finally, they emphasize that the lobby is not a cabal or a conspiracy but simply a powerful interest group like the NRA or the farm lobby. Their core argument is that the policies that the lobby pushes are not in the US' national interest, nor ultimately that of Israel. Those pieces generated extensive media coverage, and led to a wide-ranging and often polemic debate between supporters and opponents of their argument.

Mearsheimer and Walt subsequently turned the article into a book — The Israel Lobby and US Foreign Policy — which was published in late August 2007. The book has been translated into seventeen languages and published in twenty-one countries. While the book received many favorable reviews outside the United States, it did not receive any positive reviews in the American mainstream media. Some of the most positive reviews came from Israel. Mearsheimer and Walt traveled extensively throughout the United States to talk about the book. They also traveled to Canada, Europe and the Middle East.

Statements on the 2006 Lebanon War, the 2008-2009 Gaza War, and a Palestinian State

Mearsheimer was critical of Israel’s war against Lebanon in the summer of 2006. He argued that Israel’s strategy was "doomed to fail" because it was based on the "faulty assumption" that Israeli airpower could defeat Hezbollah, which was essentially a guerrilla force. The war, he argued, was a disaster for the Lebanese people, as well as a "major setback" for the United States and Israel. The lobby, he said, played a key role in enabling Israel’s counterproductive response, by preventing the United States from exercising independent influence.

Mearsheimer was also critical of Israel’s offensive against Hamas in the Gaza Strip that began in December 2008. He argued that it would not eliminate Hamas’s capability to fire missiles and rockets at Israel, and that it would not cause Hamas to end its fight with Israel. In fact, he argued that relations between Israel and the Palestinians were likely to get worse in the years ahead.

Mearsheimer emphasizes that the only hope for Israel to end its conflict with the Palestinians is to end the occupation and allow the Palestinians to have their own state in Gaza and the West Bank. Otherwise, Israel is going to turn itself into an "apartheid state", and that will be a disastrous outcome not only for Israel, but also for the United States and especially the Palestinians. In a 2010 Palestine Center lecture, Mearsheimer predicted that Israel was going to pushing American Jews into choosing between two camps, the "new Afrikaaners" who backed Israel's path to a new style of apartheid, and "righteous Jews," who advocated for a peaceful solution.

John Mearsheimer is the leading proponent of a branch of realist theory called offensive realism. Offensive realism is a structural theory which, unlike the classical realism of Hans Morgenthau, blames security competition among great powers on the hierarchy of the international system, not on human nature. In contrast to another structural realist theory, the defensive realism of Kenneth Waltz, offensive realism maintains that states are not satisfied with a given amount of power, but seek hegemony for security. Mearsheimer summed this view up in The Tragedy of Great Power Politics:

Given the difficulty of determining how much power is enough for today and tomorrow, great powers recognize that the best way to ensure their security is to achieve hegemony now, thus eliminating any possibility of a challenge by another great power. Only a misguided state would pass up an opportunity to become hegemon in the system because it thought it already had sufficient power to survive.

In this world, there is no such thing as a status quo power, since according to Mearsheimer, "a great power that has a marked power advantage over its rivals is likely to behave more aggressively because it has the capability as well as the incentive to do so." He has also dismissed democratic peace theory, which claims that democracies never or rarely go to war with one another.

Although Mearsheimer does not believe it is possible for a state to become a global hegemon, he believes states seek regional hegemony. Furthermore, he argues that states attempt to prevent other states from becoming regional hegemons, since peer competitors could interfere in a state's affairs. States which have achieved regional hegemony, such as the U.S., will act as offshore balancers, interfering in other regions only when the great powers in those regions are not able to prevent the rise of a hegemon. In a 2004 speech, Mearsheimer praised the British historian E. H. Carr for his 1939 book The Twenty Years’ Crisis and argued that Carr was correct when he claimed that international relations was a struggle of all against all with states always placing their own interests first . Mearsheimer maintained that Carr’s points were still as relevant for 2004 as for 1939, and went on to deplore what he claimed was the dominance of “idealist” thinking about international relations among British academic life

Mearsheimer has been a vocal critic of American policy toward China. Though China does not have openly militaristic ambitions today, he thinks that by trading with China and helping its economy, the United States is providing a base from which the Chinese could seriously threaten American national security in the years to come. Furthermore, he thinks that China's neighbours are increasingly worried about the growing power of China and that there are already indications that they are trying to balance China by improving ties with the United States, making the U.S. an offshore balancer. [1]

Mearsheimer's first book Conventional Deterrence (1983) addresses the question of how decisions to start a war depend on the projected outcome of military conflict. In other words, how do decision makers' beliefs about the outcome of war affect the success or failure of deterrence? Mearsheimer's basic argument is that deterrence is likely to work (function) when the potential attacker believes that a successful attack will be unlikely and costly. If the potential attacker, however, has reason to believe the attack will likely succeed and entail low costs, then deterrence is likely to breakdown. This is now widely accepted to be the way the principle of deterrence works. Specifically, Mearsheimer argues that the success of deterrence is determined by the strategy available to the potential attacker. He lays out three strategies. First, a war-of-attrition strategy, which entails a high level of uncertainty about the outcome of war and high costs for the attacker. Second, a limited-aims strategy, which entails less risks and lower costs. And, third, a blitzkrieg strategy, which provides a way to defeat the enemy rapidly and decisively, with relatively low costs. For Mearsheimer, failures in the modern battlefield are due mostly to the potential attacker's belief that it can successfully implement a blitzkrieg strategy...in which tanks and other mechanized forces are employed swiftly to effect a deep penetration and disrupt the enemy's rear. The other two strategies are unlikely to lead to deterrence failures because they would entail a low probability of success accompanied by high costs (war of attrition) or limited gains and the possibility of the conflict turning into a war of attrition (limited aims). If the attacker has a coherent blitzkrieg strategy available, however, an attack is likely to ensue, as its potential benefits outweigh the costs and risks of starting a war.

Besides analyzing cases from World War II and the Arab-Israeli conflict, Mearsheimer extrapolates implications from his theory for the prospects of conventional deterrence in Central Europe during the late Cold War. Here, he argues that a Soviet attack is unlikely because the Soviet military would be unable to successfully implement a blitzkrieg strategy. The balance of forces, the difficulty of advancing rapidly with mechanized forces through Central Europe, and the formidable NATO forces opposing such a Soviet attack made it unlikely, in Mearsheimer's view, that the Soviets would start a conventional war in Europe. Conversely, the same premise held true for NATO forces.

Nuclear proliferation

In 1990 he published a controversial essay where he predicted that Europe would revert to a multipolar environment similar to that in the first half of the Twentieth century if American and Soviet forces left following the end of the Cold War.

In this essay and in the 1993 article in Foreign Affairs The case for a Ukrainian nuclear deterrent, he argued that to reduce the dangers of war, the United States should encourage Germany and Ukraine to develop a nuclear arsenal, while working to prevent the rise of hyper-nationalism. Mearsheimer presented several possible scenarios for a post-Cold-War Europe from which American and Russian forces had departed. He believed that a Europe with nuclear proliferation was most likely to remain at peace, because without a nuclear deterrent Germany would be likely to once more try to conquer the continent (See pages 32—33). Also, he refused the possibility that the Ukraine would give up its nuclear arsenal (a remnant of the soviet stockpile there) though this in fact occurred. However in 2010 following the draft of the START Treaty, Ukraine has consented to rid of its entire former Soviet nuclear stockpile. When challenged on the former assertion at a lecture given to the International Politics department at the University of Wales in Aberystwyth, he maintained that in spite of all European integration and expansion, he still believed that his predictions would come true if the United States military left Europe.

Also, in op-ed pieces on the New York Times written in 1998 and 2000, Mearsheimer defended India's right to acquire nuclear weapons. In support of this position, he argued that India has good strategic reasons to want a nuclear deterrent, especially in order to balance against China and Pakistan, guaranteeing regional stability. He also criticized US counter-proliferation policy towards India, which he considered unrealistic and harmful to American interests in the region.

Iraq war (1991)

In January and early February 1991, Mearsheimer published two op-eds in the Chicago Tribune and the New York Times arguing that the war to liberate Kuwait from Iraqi forces should be quick and lead to a decisive US victory, with less than 1,000 American casualties. This view countered the conventional wisdom at the start of the war, that predicted a conflict lasting for months and costing thousands of American lives. Mearsheimer's argument was based on several points. First, the Iraqi Army was a Third World military, unprepared to fight mobile armored battles. Second, US armored forces were better equipped and trained. Third, US artillery was also far better than its Iraqi counterpart. Fourth, US airpower, unfettered by the weak Iraqi air force, should prove devastating against Iraqi ground forces. Fifth and finally, the forward deployment of Iraqi reserves boded ill for their ability to counter US efforts to penetrate the Iraqi defense line along the Saudi-Kuwaiti border. All these predictions came true in the course of the war.

Iraq war (2003-present)

Mearsheimer is an outspoken opponent of the Iraq War. In 2002, he was one of thirty-three professors to sign a letter in the New York Times arguing against President Bush’s intention to invade Iraq and topple Saddam Hussein from power. He felt that invading Iraq would distract from the war against al Qaeda, which he described as a greater threat to national security. The war was unnecessary, Mearsheimer felt, because the United States could continue to effectively contain Hussein, as it had done for over a decade since the Gulf War. His thinking on the matter is underpinned by a belief in a rational deterrence theory of weapons of mass destruction...namely, that there is no way by which a power with nuclear weapons equal to or less than another power can effectively coerce it into policies against its choosing (this presumes, and he holds, that Saddam Hussein was a rational actor). Mearsheimer predicted that after invading Iraq, the U.S. would need to occupy it for decades. He also wrote several Op-Ed pieces in 2003, including An Unnecessary War and Keeping Saddam in a Box in which he made the same points.

In a December 2004 interview ,Mearsheimer argued that the architects of the invasion, however misguided, weremotivated by a sincere desire to protect American interests. In his March 2006 paper with Walt (discussed in the section above on the Israel Lobby) he argued that "the war was motivated in good part by a desire to make Israel more secure".

He further wrote in an article in Foreign Policy in May 2006 Unrestricted Access:

We also traced the lobby’s impact on recent U.S. policies, including the March 2003 invasion of Iraq. Neoconservatives inside and outside the Bush administration, as well as leaders of a number of prominent pro-Israel organizations, played key roles in making the case for war. We believe the United States would not have attacked Iraq without their efforts. That said, these groups and individuals did not operate in a vacuum, and they did not lead the country to war by themselves. For instance, the war would probably not have occurred absent the September 11, 2001, terrorist attacks, which helped convince President George W. Bush and Vice President Dick Cheney to support it.