WASHINGTON -- Sen. Rick Santorum yesterday promoted his new book in a whirlwind tour of the TV talk-show circuit, stirring up speculation about his 2008 presidential ambitions by issuing a non-denial denial and managing to get some laughs (and boos) during his appearance on the fake news program "The Daily Show with Jon Stewart."

As Santorum, R-Pa., participated in an online chat with Washington Post readers yesterday afternoon to discuss his book, "It Takes a Family: Conservatism and the Common Good," a participant said he was tired of politicians denying that they were going to run for president.

"Why doesn't someone admit, 'Yes, I aspire to the highest office of my profession'?" asked the Harrisburg, Pa., reader. " ... I think the public would appreciate that honesty."

Santorum replied that he has six children between ages 4 and 14, and "the idea of coming off a race of the intensity that I am engaged in at this point [for Senate re-election] and turning around and running another two-year campaign for president is not something that I believe is in the best interest of my family.

"I believe in my heart it's my principal responsibility," he said of raising his children, "My intention is not to run in 2008."

But in saying it was not his 'intention' Santorum was following in the footsteps of other expected contenders who have used almost identical words, including Arizona Republican Sen. John McCain and Democratic Sens. Hillary Clinton of New York and Evan Bayh of Indiana.

Santorum's main focus yesterday was to generate more positive spin for his book, which has become juicy fodder for his critics since it appeared in a Washington bookstore several weeks ago.

On The Daily Show, Santorum expounded on one of the themes of his book, arguing that conservatives have "abandoned the field" on poverty and saying government should play an active role in creating more savings and wealth-creation programs that help the poor.

"So you would like to anger the left and the right," Stewart deadpanned. "You, my friend, you would like to go it alone."

Stewart challenged Santorum's view that the best way to raise children is a in family with a married mother and father.

"Can you confuse virtue with heterosexuality?" the comedian host asked. "I live in New York City. ... We are in sea of homosexuality here. ... My experience has been virtue is unrelated to sexuality."

"Certainly people who are homosexuals can be virtuous and very often are," Santorum replied. But he stood by his stance that the most stable family unit was one with married heterosexuals. "So we should have a system that builds around what's best, and that's the traditional -- what I call 'natural' --family."

"But isn't even the natural family evolving?" Stewart pressed. "... Wouldn't a monogamous, good-hearted, virtuous homosexual couple be in society's best interest in raising a child, rather than a heterosexual couple with adultery, with alcohol issues, with other things?"

Santorum stuck to his theme: "The best case everywhere is one man, one woman with their child."

"O.K, ... we can't get any further," Stewart said. "I don't think you're a bad dude; I don't think I'm a bad dude. But I literally can't convince you of the idea that I think it's doing society a disservice to dismiss the potential [of other unions]."

"I don't think anyone's dismissing the potential. I think we should honor every person in America," Santorum said. "... There's a difference, though, when it comes to changing the laws of the country that could harm children" -- referring to laws that would change the definition of marriage.