I'm reminded of the story about the young nun who asked the Mother Superior if it was all right to smoke a cigarette while praying. The Mother Superior erupted in anger at the very idea. Meekly, the nun posed a second question: "Is it all right to pray while smoking a cigarette?" That, the Mother Superior responded, is not just all right, it is commendable.

Among conservatives, there is now much wailing and gnashing of teeth over the likelihood that John McCain will become the Republican candidate for president. On such important issues as immigration, climate change, the granting of new rights to unlawful enemy combatants and freedom of political speech, McCain's positions, they say (with justification) are indistinguishable from those of a Democrat.

But imagine a Democratic presidential candidate who vehemently opposed the United States' retreat from the battle with Al-Qaida in Iraq, clearly grasped the broader threat posed by militant Islamism, favored judges who respect the authority of the Constitution and the sanctity of life, and saw merit in lower taxes and fiscal responsibility. That, a conservative might say, would be not just all right, it would be commendable.

Conservatives -- I count myself among them -- are entitled to fight for the most conservative candidate. But winning is not an entitlement. Nor is it conservative to say that if your candidate comes in second, you would just as soon return the White House to the Clintons or hand the keys to Barack Obama -- a candidate endorsed by the extremists at MoveOn.org.

Measured by a conservative's yardstick, all the Republican candidates this season have been flawed. Rudolph Giuliani revitalized New York City, but he is hardly a social conservative. Mike Huckabee is a social conservative, but he is neither an economic conservative nor a national-security hawk. Ron Paul is not a conservative at all, but rather a dogmatic libertarian (which is somewhat akin to being an obsessive-compulsive anarchist). Fred Thompson is a dyed-in-the-wool conservative, but he appeared to regard the presidency as a chore he was willing to endure rather than a challenge he was eager to embrace.

As for Mitt Romney, his supporters -- including many of my friends and colleagues -- were correct to say he was the most conservative candidate left standing, until he dropped out last week. But his critics also are correct to say he has not always seemed quite so rock-ribbed and that he didn't seem to have the knack of connecting emotionally with voters.

The conservative movement finds itself in an uncomfortable position. A conservative response would be twofold: (1) Campaign your heart out, then accept the judgment of the market in the primaries and, in the general election, don't make the perfect the enemy of the good. Support the more conservative candidate. (2) Recognize where the conservative movement has failed and strive to do better.

The fact is that most conservatives spend most of their time preaching to the converted -- principally on talk radio, in blogs and in opinion journals. Conservative think tanks offer conservative proposals to conservative lawmakers. But few strong conservatives do the hard work of attempting to bring around open-minded independents and moderate conservatives -- the voters who matter most in most elections.

This year's election will be unusually consequential. In 2006, Democrats regained control of both houses of Congress. Democrats also now hold a majority of governors' mansions and state legislatures. The left long has been regnant on America's campuses, in the mainstream news media, in the entertainment industry and in the unions.

A Clinton or Obama victory would put all levers of power into the same hands. What would Democratic Party bosses do with that? How about statehood for the District of Columbia, which would provide two new Democratic votes in the Senate? How about appointing judges who regard the Constitution as clay, and using immigration policy to expand the left's electoral margins? These and other creative maneuvers could create an anti-conservative majority that would last a generation or more.

Most worrisome of all: Americans today are engaged in a conflict as serious as any we have ever fought. McCain gets that. Perhaps Hillary Rodham Clinton does, too, though you wouldn't know it from anything she's said recently. But does Barack Obama? Or does he think it's all a big misunderstanding, one that can be resolved through talk, appeasement, global anti-poverty programs and a sincere effort to make ourselves inoffensive to those sworn to destroy us?

Thinking hard about such questions over the months ahead would be not just all right; it would be commendable -- and conservative.

Clifford D. May is president of the Foundation for the Defense of Democracies, a policy institute focusing on terrorism. His column is distributed by Scripps Howard News Service.