One of the themes of the war in Iraq that comes back again and again, like an organ chord, is religion. We hear all about the fanaticism of the suicide bombers among the Islamic fundamentalists. American religion is also a topic. President Bush is openly pious. His critics link the president’s views on domestic social issues — abortion, say, or stem-cell research — to his policy on Guantanamo Bay. On the political left, figures such as Michael Moore depict the American administration as matching Muslim zeal with the Methodist or Baptist equivalent.

The idea that religion plays a role in politics is correct. As scholar Walter Russell Mead of the Council on Foreign Relations has written over the years, President Bush is a political descendant of the seventh American president, Andrew Jackson. Mr. Bush seems hot. Jackson was hotter, clearing out whole populations ruthlessly and conducting the 19th-century Protestant version of jihad against the Creek Nation. He chattered away in as gory a fashion as a graduate of an Al Qaeda summer training camp, “The civil sword,” Jackson said, “shall and must be red and bloody.”

The religion theme can be overemphasized. Maybe the Islamofascists will prove more “fascist” and less “Islamo” than thought. And to say that President Bush’s religion is causing the Iraq War or the Lebanese conflict is going too far.

Suppose the September 11 terrorists were Italian communists. Their goal was to win worldwide victory by creating environments of political terror and economic chaos in certain key countries — not Greece or Vietnam this time, but similarly unstable domino countries such as Afghanistan, Iraq, or Lebanon. The American reaction wouldn’t be all that different from what it has been.

Defense Secretary Rumsfeld would try to roll back the communists just as earlier defense secretaries sought to roll back Maoists in Asia or contain Josef Stalin’s satellites in Europe. The language of military strategy has changed. But the doctrines are more similar than we acknowledge, regardless of the religious question.

One thing that reminds us of this was a recent HBO television special on Barry Goldwater, the former senator and presidential candidate. As a phrasemaker, the Arizona conservative ranked right up there with Jackson. Unhappy with the electorate in Washington and New York, Goldwater suggested that the country might be happier if it just sawed off the East Coast. The senator accused President Kennedy of making a “Soviet-American mutual aid society.”

What we remember about Goldwater was that he lost resoundingly to Lyndon Johnson in the 1964 race for president because his ideas were seen as too far out there. But the discordant argument is a stretch. Sure, Goldwater would have lost. But the scale of his loss had as much to do with horror at President Kennedy’s assassination as it did with Goldwater’s policies. Goldwater was a real grassroots candidate — the party establishment didn’t like him. The same voters who bought more than three million copies of his manifesto, “The Conscience of a Conservative,” persuaded their party to pick him as its nominee.

The part that is forgotten about Goldwater was that he was every bit as secular a politician as, say, Ted Kennedy or John Kerry is today. Indeed, Goldwater warned that trouble could result if America fell into “the hands of church groups,” and that religious organizations could be as bad as unions — both statements that no Republican would be caught dead uttering today.

And when it came to personal decisions Goldwater was a regular Nancy Pelosi. In the TV special, Goldwater’s daughter said she decided to have an abortion, and both the senator and his wife supported her. “Abortion,” Goldwater told Americans, “is not a conservative issue.”

Maybe Goldwaterism never stood a chance in Goldwater’s day. It stands even less of a chance now. In his new book on Republicans, “The Elephant in the Room,” syndicated columnist Ryan Sager says the political culture is shifting. In Western states, values such as freedom, independence, and privacy used to dominate the Republican Party. But now Southern values — religion and tradition — are supplanting them. Indeed, the Republican libertarians of the Southwest or Montana are already feeling so isolated that Democrats are making a play for them.

But maybe Goldwaterism — a nonreligious hawkish foreign policy and classically liberal policy at home — is due for a resurgence. So, for that matter, is realpolitik, the old pragmatic politics of, say, Richard Nixon. Goldwater detested realpolitik, which also is different from a religious approach to foreign policy.

That’s what President Bush was hinting at in his speech at the United Nations when he spoke of fighting against extremism and backing “moderates and reformers.” Listening to Mr. Bush, you almost got the sense that he longed for Henry Kissinger to amble back into the Oval Office.

In an article in the most recent edition of Foreign Affairs magazine, Mead looks at two types of American, whom he calls fundamentalists and evangelicals.

Fundamentalists, he says, are “deeply pessimistic about the prospects for world order and see an unbridgeable divide between believers and nonbelievers.”

Evangelicals, he argues, are more conciliatory — they really want to convert others. They are also more likely to turn to a trusted group of experts, the future Henry Kissingers, to manage the Middle East and to do so without sounding the religion chords.

Miss Shlaes is a columnist for Bloomberg News.