When American presidents prepare for foreign wars, they lie. Since the end of the 19th century, if not earlier, presidents have misled the public about their motives and their intentions in going to war. The enormous losses of life, property and liberty that Americans have sustained in wars have occurred in large part because of the public’s unwarranted trust in what their leaders told them before leading them into war.

In 1898, President William McKinley, having been goaded by muscle-flexing advisers and jingoistic journalists to make war on Spain, sought divine guidance as to how he should deal with the Spanish possessions, especially the Philippines, that U.S. forces had seized in what ambassador John Hay famously described as a “splendid little war.” Evidently, his prayer was answered, because the president later reported that he had heard “the voice of God,” and “there was nothing left for us to do but take them all and educate the Filipinos, and uplift and Christianize them.”

McKinley’s motivations had little if anything to do with uplifting the people whom William H. Taft, the first governor-general of the Philippines, patronizingly called “our little brown brothers,” but much to do with the political and commercial ambitions of influential expansionists such as Captain Alfred Mahan, Theodore Roosevelt, Henry Cabot Lodge and their ilk. The official apology for the brutal and unnecessary Philippine-American War was a mendacious gloss.

The Catholic Filipinos evidently did not yearn to be “Christianized,” American style, at the point of a Springfield rifle, and resisted the U.S. imperialists as they had previously resisted the Spanish imperialists. The Philippine-American War, which officially ended on July 4, 1902, but actually dragged on for many years in some islands, cost the lives of more than 4,000 U. S. troops, more than 20,000 Filipino fighters, and more than 220,000 Filipino civilians, many of whom perished in concentration camps eerily similar to the relocation camps into which U.S. forces herded Vietnamese peasants some 60 years later.

When World War I began in 1914, President Woodrow Wilson’s sympathies clearly lay with the British. Nevertheless, he quickly proclaimed U.S. neutrality and urged his fellow Americans to be impartial in both thought and deed. Wilson himself, however, leaned more and more toward the Allied side as the war proceeded. Still, he recognized that the great majority of Americans wanted no part of the fighting in Europe, and in 1916 he sought re-election successfully on the appealing slogan, “He Kept Us Out of War.”

Soon after his second inauguration, however, Wilson asked Congress for a declaration of war, which was approved, although six senators and 50 members of the House of Representatives had the wit or wisdom to vote against it. Wilson promised this would be “the war to end all wars,” but wars aplenty have taken place since the guns fell silent in 1918, leaving their unprecedented carnage—nearly 9 million dead and more than 20 million wounded, many of them hideously disfigured or crippled for life, as well as perhaps 10 million civilians who died of starvation or disease. And what did the United States or the world gain? Only a 20-year reprieve before the war’’s smoldering embers burst into flame again.

After World War I, Americans felt betrayed, and resolved never to make the same mistake again. Yet just two decades later, President Franklin Roosevelt began the maneuvers by which he hoped to plunge the nation once again into the European cauldron. Unsuccessful in his naval provocations of the Germans in the Atlantic, he eventually pushed the Japanese to the wall by a series of hostile economic-warfare measures and clearly unacceptable ultimatums, which may have induced them to mount a desperate military attack on Pearl Harbor.

Campaigning for re-election in Boston on October 30, 1940, FDR had sworn: “I have said this before, but I shall say it again and again: Your boys are not going to be sent into any foreign wars.” Well, Peleliu ain’t Peoria. Roosevelt was lying when he made his declaration, just as he had lied repeatedly before. (Stanford historian David Kennedy, careful not to speak too stridently, refers to FDR’s “frequently cagey misrepresentations to the American public.”) Yet many, many Americans trusted Roosevelt with their lives; during the war more than 400,000 paid the ultimate price.

Among FDR’s many political acolytes was a young congressman, Lyndon Baines Johnson, who eventually and, for the world, unfortunately, rose to the presidency. Like his mentor, he relied heavily on lying to the public. In October 1964, seeking to gain election by portraying himself as the “peace candidate“ (in contrast to the alleged mad bomber Barry Goldwater), LBJ told a crowd at Akron University: “We are not about to send American boys nine or ten thousand miles away from home to do what Asian boys ought to be doing for themselves.”

In 1965, however, shortly after the start of his elected term in office, Johnson exploited the Gulf of Tonkin Resolution, itself based on a fictitious account of an attack on U.S. naval forces off Vietnam, and initiated a huge buildup of U.S. forces in Southeast Asia that would eventually commit more than 500,000 American “boys” to fight an “Asian boys” war. Some 58,000 U.S. military personnel would lose their lives in the service of LBJ’s vanity and political ambitions, not to speak of the millions of Vietnamese, Cambodians, and Laotians killed and wounded.

Now President George Bush is telling the American people we stand in mortal peril of imminent attack by Iraqis or their agents armed with weapons of mass destruction. Having presented no credible evidence or compelling argument, he simply invites us to trust him, and therefore to support him as he undertakes what once would have been called naked aggression.

Well, David Hume long ago argued that just because every swan we’ve seen was white, we cannot be certain that no black swan exists. Bush may be telling the truth. In the light of history, however, we would be making a long-odds bet to believe him.