WASHINGTON -- Fred Thompson was well into a prolonged dialogue about abortion with interviewer Tim Russert on NBC's "Meet the Press" Sunday when he said something stunning for social conservatives: "I do not think it is a wise thing to criminalize young girls and perhaps their parents as aiders and abettors." He then went further: "You can't have a [federal] law" that "would take young, young girls . . . and say, basically, we're going to put them in jail."

Those comments sent e-mails flying across the country reflecting astonishment and rage by pro-life Republicans who had turned to Thompson as their best presidential bet for 2008. No anti-abortion legislation ever has proposed criminal penalties against women having abortions, much less their parents. Jailing women is a spurious issue raised by abortion rights activists. Russert did not bring it up in his questioning. What Thompson said could be expected from NARAL.

Thompson's comments revealed astounding lack of sensitivity about the abortion issue. He surely anticipated that Russert would cite Thompson's record favoring state's rights on abortion. Whether the candidate just blurted out what he said or planned it, in either case it reflects failure to realize how much his chances for the presidential nomination depend on social conservatives.

Thompson was a former senator working as television actor when on "Fox News Sunday" March 11 he made himself available for president. I started to take him seriously a month later when a religious conservative activist (call her Miss Jones because she works for a non-partisan organization) surprised me by telling me she favored Thompson to fill a void among announced presidential hopefuls. She complained that no first-tier candidate -- Rudy Giuliani, Mitt Romney or John McCain -- fit her model and that overt social conservatives -- Mike Huckabee and Sam Brownback -- could not be nominated.

I discovered broad support in April for Thompson among social conservatives, who were impressed by his 100 percent pro-life voting record during eight Senate years and could find fault only with his support for the McCain-Feingold campaign finance bill. As of Sunday, Thompson was still first in polls of conservatives by Human Events and American Values.

After Thompson's unannounced candidacy got off to a shaky start, I checked again with Miss Jones shortly after Labor Day to see whether she had changed her mind. No, she still supported Thompson, though she seemed less enthusiastic than she had been five months earlier. But Sunday's "Meet the Press" changed everything. "It was the last straw," Miss Jones told me. "I'm outraged and so are a lot of other people."

In the first question on abortion posed by Russert Sunday, he asked Thompson whether as a candidate he could run on the 2004 Republican platform that endorsed a "human life" constitutional amendment banning all abortions. "No," Thompson replied, suddenly monosyllabic. "You would not?" "No," said Thompson, adding "that's been my position the entire time I've been in politics." In fact, every Republican platform starting in 1980 has endorsed such an amendment and every Republican candidate since then has been able to run on it.

Thompson thought better of this position after the program. His campaign manager Bill Lacy told me Tuesday that Thompson "does not want to change the platform" in 2008. But there was no apology for raising the criminalization chimera. Neither Thompson nor Lacy seemed to understand that what he said antagonized the social right.

Miss Jones told me she switched off "Meet the Press" after Thompson's talk about jailing women. If she had continued, she would have heard him reiterate positions that previously had disturbed social conservatives: opposition to a constitutional amendment banning gay marriage and opposition to congressional intervention to save the life of Terri Schiavo.

Thompson's performance coincided with Republican perception of weakness in Sen. Hillary Clinton as the Democratic candidate. But where will Miss Jones go? Giuliani still defends a woman's right to choose. Romney has made the switch from pro-choice, ending previous opposition to a human life amendment. Huckabee is described by one national conservative leader as a member of the "Christian left." That leaves McCain, no favorite of the right, but the major candidate with the clearest longtime position against abortion.