Although they will be regularly deployed this campaign season, the terms "liberal" and "conservative" have largely lost analytical usefulness -- if they ever had any.

Franklin Roosevelt's New Deal is widely credited with saving capitalism during a period when revolution tempted many -- not a Communist revolution, which had minimal support, but a home-grown fascism of the Gov. Huey Long type. In early 1932 Roosevelt thought that unless he succeeded in dealing with the economic collapse he not only would be the worst president but also the last.

Roosevelt's Social Security program, implemented in 1936, is considered one of the most successful New Deal programs. President Bush's attempt in 2005 to attach Social Security to the stock market got nowhere. So is Social Security liberal or conservative?

President Harry Truman is generally called a liberal. True enough, he considered himself the heir of the New Deal, he integrated the armed forces and his 1948 platform advocated civil rights. But with George Kennan, Dean Acheson and George Marshall, Truman also put in place the elements that would win the Cold War during the presidency of Ronald Reagan: containment of the Soviet Union, the Marshall Plan, NATO, the Truman Doctrine (resisting a Communist insurgency in Greece). He answered a Communist invasion of South Korea with force. Was Truman a "liberal"?

In 1883 that great liberal, Otto Von Bismark, enacted the first modern health-care program.

We must conclude that the goal of politics, foreign and domestic, is the practical one of solving real problems as they emerge in a changing world, and this depends upon a clear analysis of the problems to be faced and the formulation of effective ways to meet them. Fact plus analysis is the basis of all successful politics.

The rationale for the invasion of Iraq was gestated in the Project for The New American Century well before George W. Bush came to the presidency in January 2001. Among a small group of theorists, Iraq was to be only the start of American global hegemony, based on "moral clarity and military force."

In February 1998, five years before the invasion of Iraq, this group of foreign policy intellectuals sent an open letter to the Clinton White House advocating a comprehensive strategy for overthrowing Saddam Hussein. Among the signers were Richard Cheney, Douglas Feith, I. Lewis Libby, Eliot Abrams, Richard Armitage, John R. Bolton, Zalmay Kalilzad, Richard Perle, Donald Rumsfeld and Paul Wolfowitz, all of whom would hold important posts in the Bush administration.

The project, founded in early 1997 by William Kristol and Robert Kagan, was inspired by the collapse of the Soviet Union in 1989 and the spread of democracy throughout the former Soviet satellites in East Europe.

William Kristol's father, Irving, a noted "neoconservative" thinker himself, did not embrace the new imperialism, writing gloomily in The Wall Street Journal in 1997 about the emergence on a global scale of a new "imperium with a minimum of moral substance."

In an Oct. 17, 2004, New York Times article, journalist Ron Suskind recalled a conversation with "a senior Bush aide" that epitomizes this imperial hubris. The aide dismissed all criticism from what he called the "reality-based community," and went on to say:

"That's not the way the world really works anymore. ... We are an empire now, and when we act we create our own reality. And while you're studying that reality -- judiciously as you will -- we'll act again, creating new realities, which you can study too, and that's how things will sort out. We're history's actors ... and you, all of you, will be left to just study what we do."

President Bush announced the first phase of the Project for a New American Century in a November 2003 speech in Britain: "The establishment of a free Iraq in the heart of the Middle East will be a watershed event in the global expansion of democracy ... as the alternative to hatred and terror."

All of this left out two realities: 1) the reality of Iraq and 2) the changing configuration of power in the world. The only consideration was what the superpower would do.

Nowhere to be found was a discussion of the history of Iraq, sectarian animosities in Iraq or the disastrous British experience there in 1920. Abundant material was available, even in a good encyclopedia, yet we went into Iraq blind, as if landing in Normandy on D-Day without knowing whether we would find there a swamp or a mountain. Nowhere was there discussion of the religious furies that an infidel occupation of a Muslim nation could arouse, sending recruits flocking to al-Qaida throughout the Islamic Middle East.

The Project for a New American Century also ignored the rise of China as an economic and military power, with reach into Africa and Latin America, and as a cultural power attracting students from around the world to Beijing University. The project actually promoted the idea of an Asian NATO to "contain China."

The project gave minor supporting roles to Japan and India, important economic powers, and the European Union, an economic power armed with nuclear weapons. Russia is now strong economically, too, with significant reserves of oil and natural gas, and it remains a formidable military power.

Then there are the 1.3 billion Muslims worldwide who have something other than an American Century on their minds. The American takeover of Iraq has further radicalized Muslims, and the small fraction of radical jihadists among them have the capability to hurt America, as 9/11 indicated.

America might be stronger militarily than any one of these power centers, but aggressive use of such power will, as always, call forth combinations of forces to oppose it.

By 2005 The New American Century had gotten lost somewhere in the vicinity of the Tigris and Euphrates rivers and by 2006 there were no new postings on the Web site of the project that envisioned its realization.

A large majority of Americans now realize that the invasion and occupation of Iraq has been a mistake, leaving more than 4,000 Americans dead, some 20,000 wounded, perhaps 200,000 Iraqis dead and 2 million in exile. Iran is stronger strategically than it was before the March 2003 invasion, and the war has cost hundreds of billions of dollars, with some estimates of indirect and follow-on costs rising to $3 trillion.

The people who opposed the Iraq war and still oppose it are called "liberals." Those who advocated it and still support it are called "conservatives."

In some broad sense on an optimism-caution spectrum (e.g., Locke vs. Hobbes) the terms may have value, but analytic realism -- fact plus analysis -- is what successful politics demands.