Non-interventionism, the diplomatic policy whereby a nation seeks to avoid alliances with other nations in order to avoid being drawn into wars not related to direct territorial self-defense, has had a long history of popularity in the government and among the people of the United States at various periods in time.
Robert Walpole, Britain's first Whig Prime Minister, proclaimed in 1723: "My politics are to keep free from all engagements as long as we possibly can." He emphasized economic advantage and rejected the idea of intervening in European affairs to maintain a balance of power. Walpole's position was known to Americans. However, during the American Revolution, the Second Continental Congress debated about forming an alliance with France. It rejected non-interventionism when it was apparent that the American Revolutionary War could be won in no other manner than a military alliance with France, which Benjamin Franklin successfully negotiated in 1778.
When Britain and France went to war in 1792, George Washington declared neutrality, with unanimous support of his cabinet, after deciding that the treaty with France of 1778 did not apply. Washington's Farewell Address of 1796 explicitly announced the policy of American non-interventionism:
President Thomas Jefferson extended Washington's ideas about foreign policy in his March 4, 1801 inaugural address. Jefferson said that one of the "essential principles of our government" is that of "peace, commerce, and honest friendship with all nations, entangling alliances with none."
In 1823, President James Monroe articulated what would come to be known as the Monroe Doctrine, which some have interpreted as non-interventionist in intent: "In the wars of the European powers, in matters relating to themselves, we have never taken part, nor does it comport with our policy, so to do. It is only when our rights are invaded, or seriously menaced that we resent injuries, or make preparations for our defense."
After Tsar Alexander II put down the 1863 January Uprising in Poland, French Emperor Napoleon III asked the United States to "join in a protest to the Tsar." Secretary of State William H. Seward declined, "defending 'our policy of non-intervention—straight, absolute, and peculiar as it may seem to other nations,'" and insisted that "[t]he American people must be content to recommend the cause of human progress by the wisdom with which they should exercise the powers of self-government, forbearing at all times, and in every way, from foreign alliances, intervention, and interference."
The United States' policy of non-intervention was maintained throughout most of the 19th century. The first significant foreign intervention by the US was the Spanish–American War, which ultimately resulted in the Philippine–American War from 1899–1902.
The President of the United States Woodrow Wilson, after winning reelection with the slogan "He kept us out of war," was able to navigate neutrality in World War I for about three years. Early on, their historic shunning of foreign entanglements, and the presence in the US of immigrants with divided loyalties in the conflict helped maintain neutrality. Various causes compelled American entry into World War I, and Congress would vote to declare war on Germany; this would involve the nation on the side of the Triple Entente, but only as an "associated power" fighting the same enemy, not one officially allied with them. A few months after the declaration of War, Wilson gave a speech to congress outlining his aims to end the conflict, labeled the Fourteen Points. While this American proclamation was less triumphalist than the aims of some of its allies, it did propose in the final point, that a general association of nations must be formed under specific covenants for the purpose of affording mutual guarantees of political independence and territorial integrity to great and small states alike. After the war, Wilson traveled to Europe and stayed for months to labor on the post-war treaty; no president had previously enjoined such sojourn outside of the country. In that Treaty of Versailles, Wilson's association was formulated as the League of Nations.
In the wake of the First World War, the non-interventionist tendencies of US foreign policy gained ascendancy. The Treaty of Versailles, and thus, United States' participation in the League of Nations, even with reservations, was rejected by the Republican-dominated Senate in the final months of Wilson's presidency. A group of Senators known as the Irreconcilables, identifying with both William Borah and Henry Cabot Lodge, had great objections regarding the clauses of the treaty which compelled America to come to the defense of other nations. Lodge, echoing Wilson, issued 14 Reservations regarding the treaty; among them, the second argued that America would sign only with the understanding that:
Nothing compels the United States to ensure border contiguity or political independence of any nation, to interfere in foreign domestic disputes regardless of their status in the League, or to command troops or ships without Congressional declaration of war.
Although the United States was unwilling to commit to the League of Nations, they continued to engage in international negotiations and treaties. In August 1928, fifteen nations signed the Kellogg–Briand Pact, brainchild of American Secretary of State Frank Kellogg and French Foreign Minister Aristide Briand. This pact that was said to have outlawed war and showed the United States commitment to international peace had its semantic flaws. For example, it did not hold the United States to the conditions of any existing treaties, it still allowed European nations the right to self-defense, and it stated that if one nation broke the Pact, it would be up to the other signatories to enforce it. The Kellogg–Briand Pact was more of a sign of good intentions on the part of the US, rather than a legitimate step towards the sustenance of world peace.
The economic depression that ensued after the Crash of 1929, also continued to abet non-intervention. The attention of the country focused mostly on addressing the problems of the national economy. The rise of aggressive expansionism policies by Fascist Italy and the Empire of Japan led to conflicts such as the Italian conquest of Ethiopia and the Japanese invasion of Manchuria. These events led to ineffectual condemnations by the League of Nations. Official American response was muted. America also did not take sides in the brutal Spanish Civil War.
As Europe moved closer to war in the late 1930s, the United States Congress continued to demand American neutrality. Between 1936 and 1937, much to the dismay of President Roosevelt, Congress passed the Neutrality Acts. For example, in the final Neutrality Act, Americans could not sail on ships flying the flag of a belligerent nation or trade arms with warring nations. Such activities had played a role in American entrance into World War I.
On September 1, 1939, Germany invaded Poland; Britain and France subsequently declared war on Germany, marking the start of World War II. In an address to the American People two days later, President Roosevelt assured the nation that he would do all he could to keep them out of war. However, his words showed his true goals. "When peace has been broken anywhere, the peace of all countries everywhere is in danger," Roosevelt said. Even though he was intent on neutrality as the official policy of the United States, he still echoed the dangers of staying out of this war. He also cautioned the American people to not let their wish to avoid war at all costs supersede the security of the nation.
The war in Europe split the American people into two camps: non-interventionists and interventionists. The two sides argued over America's involvement in this World War II. The basic principle of the interventionist argument was fear of German invasion. By the summer of 1940, France suffered a stunning defeat by Germans, and Britain was the only democratic enemy of Germany. In a 1940 speech, Roosevelt argued, "Some, indeed, still hold to the now somewhat obvious delusion that we … can safely permit the United States to become a lone island … in a world dominated by the philosophy of force." A national survey found that in the summer of 1940, 67% of Americans believed that a German-Italian victory would endanger the United States, that if such an event occurred 88% supported "arm[ing] to the teeth at any expense to be prepared for any trouble", and that 71% favored "the immediate adoption of compulsory military training for all young men".
Ultimately, the ideological rift between the ideals of the United States and the goals of the fascist powers empowered the interventionist argument. Writer Archibald MacLeish asked, "How could we sit back as spectators of a war against ourselves?" In an address to the American people on December 29, 1940, President Roosevelt said, "the Axis not merely admits but proclaims that there can be no ultimate peace between their philosophy of government and our philosophy of government."
However, there were still many who held on to non-interventionism. Although a minority, they were well organized, and had a powerful presence in Congress. Pro-German or anti-British opinion contributed to non-interventionism. Roosevelt's national share of the 1940 presidential vote declined by seven percentage points from 1936. Of the 20 counties in which his share declined by 35 points or more, 19 were largely German-speaking. Of the 35 counties in which his share declined by 25 to 34 points, German was the largest or second-largest original nationality in 31. Non-interventionists rooted a significant portion of their arguments in historical precedent, citing events such as Washington's farewell address and the failure of World War I. "If we have strong defenses and understand and believe in what we are defending, we need fear nobody in this world," Robert Maynard Hutchins, President of the University of Chicago, wrote in a 1940 essay. Isolationists believed that the safety of the nation was more important than any foreign war.
As 1940 became 1941, the actions of the Roosevelt administration made it more and more clear that the United States was on a course to war. This policy shift, driven by the President, came in two phases. The first came in 1939 with the passage of the Fourth Neutrality Act, which permitted the United States to trade arms with belligerent nations, as long as these nations came to America to retrieve the arms, and pay for them in cash. This policy was quickly dubbed, 'Cash and Carry.' The second phase was the Lend-Lease Act of early 1941. This act allowed the President "to lend, lease, sell, or barter arms, ammunition, food, or any 'defense article' or any 'defense information' to 'the government of any country whose defense the President deems vital to the defense of the United States.'" American public opinion supported Roosevelt's actions. As United States involvement in the Battle of the Atlantic grew with incidents such as the sinking of the USS Reuben James (DD-245), by late 1941 72% of Americans agreed that "the biggest job facing this country today is to help defeat the Nazi Government", and 70% thought that defeating Germany was more important than staying out of the war.
After the attack on Pearl Harbor caused America to enter the war in December 1941, isolationists such as Charles Lindbergh's America First Committee and Herbert Hoover announced their support of the war effort. Isolationist families' sons fought in the war as much as others.
During the presidency of Barack Obama, some members of the United States federal government, including President Obama and Secretary of State John Kerry, considered intervening militarily in the Syrian Civil War. A poll from late April 2013 found that 62% of Americans thought that the "United States has no responsibility to do something about the fighting in Syria between government forces and antigovernment groups," with only twenty-five percent disagreeing with that statement. A writer for The New York Times referred to this as "an isolationist streak," a characterization international relations scholar Stephen Walt strongly objected to, calling the description "sloppy journalism." According to Walt, "the overwhelming majority of people who have doubts about the wisdom of deeper involvement in Syria—including yours truly—are not 'isolationist.' They are merely sensible people who recognize that we may not have vital interests there, that deeper involvement may not lead to a better outcome and could make things worse, and who believe that the last thing the United States needs to do is to get dragged into yet another nasty sectarian fight in the Arab/Islamic world."
In December 2013, the Pew Research Center reported that their newest poll, "American's Place in the World 2013," had revealed that 52 percent of respondents in the national poll said that the United States "should mind its own business internationally and let other countries get along the best they can on their own." This was the most people to answer that question this way in the history of the question, one which pollsters began asking in 1964. Only about a third of respondents felt this way a decade ago.
A July 2014 poll of "battleground voters" across the United States found "77 percent in favor of full withdrawal from Afghanistan by the end of 2016; only 15 percent and 17 percent interested in more involvement in Syria and Ukraine, respectively; and 67 percent agreeing with the statement that, 'U.S. military actions should be limited to direct threats to our national security.'"
Rathbun (2008) compares three separate themes in conservative policies since the 1980s: conservatism, neoconservatism, and isolationism. These approaches are similar in that they all invoked the mantle of "realism" and pursued foreign policy goals designed to promote national interests. Conservatives, however, were the only group that was "realist" in the academic sense in that they defined the national interest narrowly, strove for balances of power internationally, viewed international relations as amoral, and especially valued sovereignty. By contrast, neoconservatives based their foreign policy on nationalism, and isolationists sought to minimize any involvement in foreign affairs and raise new barriers to immigration. Former Republican Congressman Ron Paul favored a return to the non-interventionist policies of Thomas Jefferson and frequently opposed military intervention in countries like Iran and Iraq.