WASHINGTON -- Fred Thompson's plunge into the presidential pool -- more bellyflop than swan dive -- was the strangest product launch since that of New Coke in 1985. Then the question was: Is this product necessary? A similar question stumped Thompson the day he plunged.

Sean Hannity, who is no Torquemada conducting inquisitions of conservatives, asked Thompson: "When you look at the other current crop of candidates -- Republicans -- where is the distinction between your positions and what you view as theirs?" Thompson replied: "Well, to tell you the truth, I haven't spent a whole lot of time going into the details of their positions."

He also is unfamiliar with the details of his own positions. Consider his confusion the next day when talk radio host Laura Ingraham asked him about something he ardently supported -- the McCain-Feingold expansion of government regulation of political speech. His rambling, incoherent explanation was just clear enough to be alarming about what he believes, misremembers and does not know.

Thompson said he had advocated McCain-Feingold to prevent, among other things, corporations and labor unions from "giving large sums of money to individual politicians." But corporate and union contributions to individual candidates were outlawed in 1907 and 1947, respectively.

Ingraham asked about McCain-Feingold's ban on issue ads that mention a candidate close to an election. He blamed an unidentified "they" who "added on" that provision, which he implied was a hitherto undiscussed surprise. But surely he knows that bills containing the ban had been introduced in previous sessions of Congress before passage in 2002.

In 1997, Thompson chaired a Senate committee investigating 1996 election spending. In its final report, issued in 1998, Thompson's committee recommended a statutory "restriction on issue advocacy" during "a set period prior to an election" when the speech includes "any use of a candidate's name or image." And in 1999, Thompson co-sponsored legislation containing what became, in 2002, the McCain-Feingold blackout periods imposed on any television or radio ad that "refers to" a candidate for federal office -- a portion of which the Supreme Court in June declared unconstitutional.

Thompson, contrary to his current memories, was deeply involved in expanding government restrictions on political speech generally and the ban on issue ads specifically. Yet he told Ingraham "I voted for all of it," meaning McCain-Feingold, but said "I don't support that" provision of it.

Oh? Why, then, did he file his own brief urging the Supreme Court to uphold McCain-Feingold, stressing Congress' especially "compelling interest" in squelching issue ads that "influence" elections?

Most lamely, Thompson takes credit for McCain-Feingold doubling the amount of "hard money" an individual can give to a candidate, which he says reduces the advantages of incumbency. But that is absurd: Most hard money flows to incumbents.

Ingraham asked why government should be telling individuals how much they can give to fund political speech by candidates they support. Thompson replied: "Why should the government ... tell a loan officer that he cannot accept money from someone trying to get a loan from him ... and then go ahead and give that person a loan? ... I mean, it's bribery in the real world."

So he believes, as zealous regulators of political speech do, that political contributions are incipient bribes -- but that bribery begins with contributions larger than $2,300. Which brings us to the financial implausibility of his late-starting campaign.

Suppose he does something unprecedented -- gets 100 people a day, from now until Jan. 1, to contribute the permitted maximum of $2,300. After subtracting normal fundraising costs and campaign overhead, he would still enter 2008 vulnerable to being outspent at least three-to-one by his major rivals.

Is there, however, a huge cash value in the role for which he is auditioning -- darling of religious conservatives? Perhaps. But their aspiring darling recently said in South Carolina, "I attend church when I'm in Tennessee. I'm in McLean right now. I don't attend regularly when I'm up there."

"Right now"? He has been living "up there" in that upscale inside-the-Beltway Washington suburb, honing his "Aw, shucks, I'm just an ol' Washington outsider" act, for years. Long enough to have noticed that McLean is planted thick with churches. Going to church is, of course, optional -- unless you are aiming to fill some supposed piety void in the Republican field.

New Coke was announced on April 23, 1985, with the company's president piling on adjectives usually reserved for Lafite Rothschild -- "smoother, rounder yet bolder." Almost 80 days later, the public having sampled it, the company pulled the product from stores. Perhaps Thompson's candidacy will last longer than New Coke did.