WASHINGTON -- Arthur Balfour, the British statesman, once said that a rival's clarity was a liability because he had nothing to say. As the presidential nomination contests approach a crescendo, some candidates are making themselves perilously clear, one of them with the help of her helpmate.

Last Tuesday, Bill Clinton, trying to whet Iowans' appetites for another Clinton presidency, announced/discovered/remembered that he opposed the Iraq War "from the beginning," thereby revealing disharmony with his spouse, who voted for it. Backward reels the mind, to 1992, when Gov. Clinton explained his opinion of Congress' 1991 authorization of the Gulf War: "I guess I would have voted with the majority if it was a close vote. But I agree with the arguments the minority made."

Such muddiness clarifies: Do voters who are weary of the scary clarity of the current president's certitudes really want to replace them with a recurrence of the hairsplitting evasions that created the adjective "Clintonian"?

About one thing, Hillary Clinton is, remarkably, both clear and opaque: Jefferson is anachronistic. "We can talk all we want about freedom and opportunity, about life, liberty and the pursuit of happiness, but what does all that mean to a mother or father who can't take a sick child to the doctor?" Well, OK, what does "all that" mean to someone stuck in congested traffic? Or annoyed by the price of cable television? What does Mrs. Clinton mean?

John Edwards' health care agenda involves un-Jeffersonian bossiness. "It requires," he says, "that everybody get preventive care. If you are going to be in the system, you can't choose not to go to the doctor for 20 years." In an ad running in Iowa, Edwards brandishes his mailed fist at Congress, to which he vows to say: "If you don't pass universal health care by July of 2009, in six months, I'm going to use my power as president to take your health care away from you."

What power would that be? What power enables presidents to "take" health care from people who have it by statute? This is the Democrats' riposte to the grandiosity of the current president's notion of executive prerogatives?

Edwards might, however, reconsider -- he is, after all, a serial apologizer. Of his actions during his six years in the Senate, he says: My vote for the Iraq War? Sorry about that. For the Patriot Act? I don't know what I was thinking. For No Child Left Behind? Oops! For liberalized trade with China? Forgive me. For storing waste in Nevada's Yucca Mountain? I was for it before I was against it.

On the Republican side, Mike Huckabee's candidacy rests on serial non sequiturs: I am a Christian, therefore I am a conservative, therefore whatever I have done or propose to do with "compassionate," meaning enlarged, government is conservatism. And by the way, anything I denote as a "moral" issue is beyond debate other than by the uncaring forces of greed. His is a moralist's version of the intellectual vanity once ascribed to Oxford's Benjamin Jowett:

My name is Jowett

Of Balliol College;

If I don't know it,

It is not knowledge.

Many Iowans think it would be wise to nominate a candidate who, when the Republicans were asked during a debate to raise their hands if they do not believe in evolution, raised his. But, then, Huckabee believes America can be energy independent in 10 years, so he has peculiar views about more than paleontology.

Huckabee combines pure moralism with incoherent populism: He wants Washington to impose a nationwide ban on smoking in public, show more solicitude for Americans of modest means, and impose more protectionism, thereby raising the cost of living for Americans of modest means.

Although Huckabee is considered affable, two subliminal but clear enough premises of his Iowa attack on Mitt Romney are unpleasant: The almost 6 million American Mormons who consider themselves Christians are mistaken about that. And -- 55 million non-Christian Americans should take note -- America must have a Christian president.

Another pious populist who was annoyed by Darwin -- William Jennings Bryan -- argued that William Howard Taft, his opponent in the 1908 presidential election, was unfit to be president because he was a Unitarian, a persuasion sometimes defined as the belief that there is at most one God. The electorate chose to run the risk of entrusting the presidency to someone skeptical about the doctrine of the Trinity.

If Huckabee succeeds in derailing Romney's campaign by raising a religious test for presidential eligibility, that will be clarifying: In one particular, America was more enlightened a century ago.