The embattled speaker of the House, Dennis Hastert, is taking the offensive, effectively gambling the Republican Party’s congressional majority on his ability to weather the roiling political storm over X-rated computer messages sent to former Capitol pages by a Republican congressman from Florida, Mark Foley.

Mr. Hastert called a news conference in his home district yesterday to express regret for the page scandal while insisting that he will not give up his leadership post. “I’m deeply sorry that this has happened and the bottom line is we’re taking responsibility,” the speaker told reporters gathered outside one of his offices, in Batavia, Ill.

Asked under what circumstances he would resign, Mr. Hastert said, “Ultimately, anytime that a person has to be a leader on the hot seat and he is a detriment to the party, there ought to be a change. I became speaker in a situation like that. I don’t think that’s the case. I said I haven’t done anything wrong, obviously.”

In an interview published yesterday, Mr. Hastert suggested that loyal Republicans should focus on why many of the messages Mr. Foley sent did not surface until weeks before the November election.

“When the base finds out who’s feeding this monster, they’re not going to be happy,” Mr. Hastert told the Chicago Tribune. “The people who want to see this thing blow up are ABC News and a lot of Democratic operatives, people funded by George Soros.” The speaker’s mention of Mr. Soros, a billionaire financier and philanthropist, seemed to be a reference to an organization he has funded, Citizens for Responsibility and Ethics in Washington. The liberal watchdog group has said it obtained some e-mails from Mr. Foley to a former page in July and immediately turned them over to the FBI.

“The implication that I had something to do with this scandal is so far off the mark that it’s really laughable,” Mr. Soros told Fox News yesterday. “It’s a feeble attempt to divert attention from him and his responsibility.”

Late yesterday, Mr. Hastert got another public vote of confidence from President Bush, who telephoned the speaker to endorse his response to the affair. Mr. Bush thanked Mr. Hastert “for making a clear public statement today, taking responsibility, and saying that the House leadership is accountable to the American people,” a White House spokeswoman, Nicole Guillemard, said.

Earlier in the day, the White House press secretary, Tony Snow, downplayed the electoral significance of the sexually explicit instant messages sent to former pages by Mr. Foley, who resigned last week after some of the exchanges were made public.

“The question is whether people are going to be voting on the basis of disgusting IMs between a grown man and a young man, or something that’s probably more important to everybody, which is safety, security, and prosperity,” the spokesman said.

New tales of sordid solicitations by Mr. Foley emerged yesterday, as ABC reported three more young men are claiming to have received e-mails or instant messages from the congressman after leaving the page program. One said he was 17 when he got a message inquiring about the penis sizes of his page roommates. According to ABC, another ex-page said the congressman “asked me for photographs of my … penis.” The network did not name the former pages.

The House’s ethics committee launched a probe into the affair yesterday, voting to issue nearly four dozen subpoenas for documents and testimony.

“We pledge to you that our investigation will go wherever the evidence leads us,” the Republican chairman of the panel, Rep. Doc Hastings of Washington, said.

“We’re dealing with children,” the ranking Democrat, Rep. Howard Berman of California, said. “We are, the Congress is, in loco parentis here. There appears to be something gone terribly wrong.”

Mr. Berman said he hoped the probe would be complete in a matter of weeks, but there were no promises it would be wrapped up by Election Day.

Highlighting the difficulties inherent in an investigation of fellow lawmakers, Mr. Hastings first gave a ringing endorsement to Mr. Hastert and later qualified the statement. “I think the speaker has done an excellent job,” the congressman said in response to a reporter’s question. Mr. Hastings later said he was giving a general evaluation of Mr. Hastert and was not expressing a view on his handling of matters involving Mr. Foley.

Evidence of cleavages among House Republicans remained on display yesterday. Mr. Hastert sounded irritated when asked about comments made by a GOP congressman from Missouri, Roy Blunt, who said he would have investigated an initial report about Mr. Foley more aggressively. “I appreciate Roy’s help on this,” Mr. Hastert said on a radio program hosted by a conservative commentator, Laura Ingraham. “It seems like a lot of this advice comes in 20/20 hindsight.”

Mr. Hastert said he has canceled all of his planned fund-raising appearances for next week, a move that he acknowledged would hurt GOP candidates.

Rep. Charles Rangel of Manhattan told The New York Sun yesterday that Mr. Hastert “has already lost,” regardless of whether he chooses to resign. “So many people told the speaker” about Mr. Foley’s inappropriate interest in pages, Mr. Rangel said. “If he can’t remember those important people, he’s got a real mental problem.”

The chairman of the Republican Party in New York, Stephen Minarik, also jumped into the fray yesterday, asserting that Democrats were making a “gross political miscalculation” by trying to capitalize on the Foley affair. In a statement, Mr. Minarik said Democrats looked the other way at sexual misconduct by members of their party, including an episode from the 1980s in which a Democratic lawmaker, Gerry Studds, “proudly admitted to having sex with a 17-year-old male page.”

The GOP official also cited President Clinton’s commutation of the sentence of an Illinois congressman, Melvin Reynolds, who served five years in prison for having sex with a 16-year-old campaign worker. The commutation applied to federal bank fraud charges unrelated to the sex offenses.

Not all Republicans endorsed Mr. Hastert’s strategy of trying to blame liberals in the press and in Democratic circles for stirring up the Foley affair in advance of the election. Ms. Ingraham, for instance, told the speaker she was dubious of efforts to shift blame for the episode.

“I have a real problem with Republicans who are saying, ‘Well, it’s the vast left-wing conspiracy out there,'” she said. “That’s what the Clintons did and I didn’t much care for it when the Clintons did it.”

A Time magazine poll conducted this week found that a quarter of those surveyed said they were less likely to support GOP House candidates because of the Foley scandal. Those polled were split just about evenly on whether Mr. Hastert should resign.

Political analysts have cautioned that the impact of the affair is difficult to measure in a national poll because only a few dozen races are close enough to be affected by the unfolding saga.

Mr. Hastert had planned to announce yesterday that the page program would be overhauled by a former FBI director, Louis Freeh. However, the speaker dropped the idea, at least for now, after the Democratic leader in the House, Nancy Pelosi of California, balked.

A spokeswoman said Ms. Pelosi viewed Mr. Freeh as “the wrong person” to undertake such an effort because he lacked expertise about exploited children. “The issue isn’t that the rules weren’t adequate, but that they weren’t followed,” the spokeswoman, Jennifer Crider, said. She said ill will between Mr. Freeh and prominent Democrats, including Mr. Clinton, did not impact Ms. Pelosi’s position.