Washington ? For some Republicans, Howard Dean’s supremacy among Democratic presidential aspirants — $10 million expected to be raised in the July-September quarter; a 21-point lead in New Hampshire — causes merriment. They think a Dean nomination, featuring opposition to the war, enthusiasm for higher taxes and approbation for same-sex civil unions, would mean four more years of what Dean considers the Bush-Ashcroft Terror.

Unless Dean wins. Which is unthinkable.

As unthinkable as a twice-defeated Senate candidate from Illinois, whose single congressional term was more than a decade earlier, being elected president with 39.9 percent of the vote. As unthinkable as a vice president losing a presidential race, then a California gubernatorial race, then six years later winning the presidency. As unthinkable as a movie actor becoming president.

A Dean presidency is not inconceivable. Granted, it is unlikely for reasons that make it undesirable. He may not wear well with the public. If he is half as bright as he thinks he is, he is very bright. And his is no uncertain trumpet: the brio with which he proclaims his beliefs proves that he is not paralyzed by the difference between certitude and certainty.

But there is danger as well as benefit for Dean in his very Deanness. The obverse of his high opinion of himself is his low opinion of President Bush. So he probably would sigh, or do the functional equivalent.

If Al Gore had not expressed his disdain for Bush by those exasperated sighs during the first debate, Gore might be president. But Gore had to sigh. Expressing disdain of Bush was for Gore a sensual delight, almost a metabolic necessity. It might be for Dean, too. But most of the electorate would be unforgiving of bad manners toward any president.

Another potential Dean weakness, implicating his political judgment, is suggested by believable reports that he admires retired Gen. Wesley Clark, former NATO commander. Dean, more than any other possible Democratic nominee, might need a running mate who would assuage anxieties about a former Vermont governor’s lack of national security experience.

Other Democrats see Clark as a solution to a problem their party has had since the McGovernite takeover in 1972, the problem of voters’ doubts about its competence regarding national security. But the fact that Clark is the kind of military man who appeals to Democrats — and that they appeal to him — helps explain why the party has that problem.

Comparisons of Clark to Dwight Eisenhower are ludicrous. Eisenhower, as well-prepared as any president for the challenges of his era, had spent three years immersed in the political complexities of coalition warfare, dealing with Roosevelt, Churchill, Stalin, de Gaulle and others. Clark’s claim to presidential stature derives from directing NATO’s 78 days of war at 15,000 feet over Serbia. It was the liberals’ dream war: tenuously related to U.S. security, its overriding aim, to which much was sacrificed, was to have zero U.S. fatalities.

As Clark crisscrosses the country listening for a clamor for him (“I expect to have my decision made by Sept. 19,” when he visits Iowa — feel the suspense), he compounds the confusion that began when he said (June 15, 2003) that on 9-11 “I got a call at my home” saying that when he was to appear on CNN, “You’ve got to say this is connected” to Iraq. “It came from the White House, it came from people around the White House. It came from all over.” But who exactly called Clark?

July 1: “A fellow in Canada who is part of a Middle Eastern think tank.” There is no such Canadian institution. Anyway, who “from the White House”? “I’m not going to go into those sources. … People told me things in confidence that I don’t have any right to betray.”

July 18: “No one from the White House asked me to link Saddam Hussein to Sept. 11.”

Aug. 25: It came from “a Middle East think tank in Canada, the man who’s the brother of a very close friend of mine in Belgium. He’s very well connected to Israeli intelligence. … I haven’t changed my position. There’s no waffling on it. It’s just as clear as could be.”

Now Clark darkly says there are “rumors” that in February “the White House” tried — well, “apparently” tried — “to get me knocked off CNN.” Clark still coyly refuses to say he is a Democrat but forthrightly confesses to being a “centrist.” As he prepares to heed the clamor for him to join the pursuit of Dean, he is earning the description National Review has given to Sen. Bob Graham: “a deranged moderate.”