WASHINGTON — WASHINGTON -- When House Republican leaders gathered last week for a news conference on the steps of the Capitol, it was supposed to be a Memorial Day salute to veterans. But the event quickly deteriorated as reporters crowded around beleaguered House Speaker Dennis Hastert of Illinois. They shouted questions about whether he was under investigation in a lobbying scandal and whether he would sue the television network that reported he was. "That's something my lawyers are taking care of right now," answered Hastert, who was so pressured by the media swarm that he had difficulty shaking hands with the veterans being honored. It was a telling moment in a week that saw Hastert, who for years has been a loyal Bush lieutenant and a calming influence in his party, turn into a vocal critic of the administration and become the center of controversy himself. Hastert threatened to sue ABC for libel after the network aired its report - later denied by the Justice Department - that he was under investigation in the Jack Abramoff influence-peddling scandal. And Hastert angrily accused department officials of trying to intimidate him by leaking a false accusation to ABC. The speaker had earlier taken the lead in challenging the FBI's authority to raid the congressional office of Rep. William Jefferson, a Louisiana Democrat who is being investigated in a corruption probe. He pressured Bush to agree Thursday to seal records seized from Jefferson's office and negotiate with Congress on how to handle them. That happened even as top law enforcement officials implied they would resign before they would give back the records. House Republicans cheered Bush's decision to seal the records seized from Jefferson's office because they believed the raid violated Congress' prerogatives. But some worried that the constitutional victory for Hastert would be a public relations problem for the rest of them. They fear that the nuances of constitutional principle will mean little to voters who conclude that the GOP - which aims to be the "law-and-order" party - is now on the wrong side of the law by challenging law enforcement officials pursuing a bribery investigation. "It's a challenge" to explain to constituents, said Rep. David Dreier, a California Republican. "People are painting this as members of Congress being above the law." The dissent among House Republicans stands in striking contrast to the unshakeable party unity that Republicans showed during Bush's first term. In addition to the president's popularity among Republicans and the iron-fisted party discipline enforced by then-House Majority Leader Tom DeLay of Texas, there was Hastert, a steady and well-liked leader who could bring party factions together. Hastert, 64, was viewed as so important to Bush's second term that the White House urged him to set aside thoughts of retiring before 2008. In Bush's second term, all that has changed. Public support for Bush and his policies has dropped precipitously, even among conservatives. DeLay stepped down as leader last year because he was indicted on money laundering charges, and he is about to quit Congress. House Republicans - including Hastert - increasingly see their political interest as distinct from Bush's, because he will never again stand for election. At a time when Hastert's support is more important than ever in maintaining party unity, he has been increasingly willing to defy the White House. He was a leading critic of a deal that would have allowed an Arab company to manage operations in several U.S. ports. He criticized the administration's choice of Gen. Michael Hayden to replace Porter Goss (a Hastert friend and former congressman) as CIA director. Hastert also opposes the administration's plan to allow illegal immigrants to become citizens. Hastert surprised many when he criticized the FBI raid on Jefferson's office, because in doing so he seemed to be siding with a Democrat accused of corruption. Hastert argued it was his job to defend Congress' institutional prerogatives and said the search violated the constitutional separation of powers for the executive branch to be rifling through legislative files. He took his case directly to Bush in at least two conversations last week, according to a Hastert aide. The issue prompted Hastert's staff to make a rare effort to reach out to House Democratic Leader Nancy Pelosi, a California Democrat, with whom Republicans have been locked in partisan combat for years. The adversaries collaborated in Hastert's Capitol office Wednesday to craft a joint statement asking the FBI to return the materials seized from Jefferson's office. But that evening, ABC reported that Hastert was under investigation as part of the Abramoff inquiry because of a letter he had signed urging the Interior Department to block an Indian casino opposed by one of Abramoff's clients. The usually unflappable denied the report flatly, and soon the Justice Department issued a statement backing him up. By Thursday morning, he suggested to Chicago radio listeners that the report was based on a leak intended to intimidate him as he was challenging the FBI's raid. The episode sent a wave of anxiety among some lawmakers who thought Hastert was coming under scrutiny for what they saw as a routine comment letter. Rep. Sherwood Boehlert, a New York Republican, said the letter Hastert had signed was one he would have signed "in a heartbeat." "There but for the grace of God go I," said Boehlert. Janet Hook and Faye Fiore write for the Los Angeles Times.