WASHINGTON — While the White House is blaming the Democratic leadership for the collapse of the immigration bill, Senator McCain is directing his ire at members of his own party.

The Arizona senator, asked yesterday to explain the bill’s failure last week, cited the work of “the more conservative, anti-immigrant, anti-legislation group” of lawmakers who defeated the proposal in Congress.

“I think the Senate works in a way where relatively small numbers can block legislation, but I also think the more conservative, anti-immigrant, anti-legislation group were very well backed up by a very vocal group of people who were supporting them,” Mr. McCain said on ABC’s “This Week.”

The senator had been a chief proponent of the immigration bill, a compromise that would have tightened border security and established a temporary “guest worker” program while offering legal status and a chance for citizenship to many of the estimated 12 million illegal immigrants now in the country. Many conservatives have strongly opposed the bill, deriding it as “amnesty,” and the issue has dogged Mr. McCain’s bid for the Republican presidential nomination.

The Senate majority leader, Harry Reid, pulled the bill from the Senate floor last week after it failed a second test vote to limit debate. Mr. McCain’s reaction has differed from that of the White House, which has expressed disappointment in Mr. Reid for not allowing a longer period of debate on the bill.

Mr. Reid has faulted Republicans, saying they were trying to stall action on the bill by offering too many amendments.

The White House press secretary, Tony Snow, yesterday questioned why the majority leader pulled the bill when he did.

Mr. Snow criticized the Democrats’ plan to hold instead what he called a “purely symbolic” no-confidence vote on Attorney General Gonzalez and said the immigration bill would have taken only another two days to complete.

“Rather than doing finger pointing, if Harry Reid is committed to this — and this is an historic bill dealing with a problem that a lot of people think has to be solved, and it’s got to be solved in a smart way — why not go ahead and set aside those two days for debate?” Mr. Snow said on “Fox News Sunday.”

Mr. Snow said President Bush remains committed to the bill and will speak to Senate Republicans about it tomorrow. The president dedicated his Saturday radio address to immigration, expressing hope that the legislation will ultimately pass.

The secretary of commerce, Carlos Gutierrez, was even more emphatic yesterday. “This bill is alive and well, and we are more determined than ever to get it through,” he said on CNN’s “Late Edition.”

Mr. Reid has said he is open to bringing the legislation back to the floor, but he has not specified when.

In the ABC interview, Mr. McCain also criticized his two top rivals for the Republican nomination, Mayor Giuliani and Mitt Romney, for opposing the bill. “It was not consistent with their records as I read it,” he said. “Both of them had come out in principle for the components of this legislation.”

Mr. McCain’s comments followed last week’s Republican debate, where he sparred with a number of his competitors over immigration.

He defended the compromise legislation, although he said, “It was not the bill I would have written.”

Mr. Giuliani has said the bill lacks a “unifying purpose” and provides for inadequate identification of illegal immigrants, while Mr. Romney has assailed the part of the legislation that grants provisional legal status to millions of undocumented people.

“One minute Senator McCain is chiding those who oppose the bill on principle, the next minute he’s saying it’s not the bill he would have written,” a spokesman for Mr. Romney, Kevin Madden, said yesterday in response to Mr. McCain’s comments. “If that reasoning sounds confusing, it’s probably because it is.”

By criticizing fellow Republicans over the failure of the immigration bill, Mr. McCain may run the risk of deepening a rift he has opened with conservatives who have long opposed his position on the issue. “He would be better off attacking the Democrats,” the director of the University of Virginia’s Center for Politics, Larry Sabato, said.

Mr. McCain’s response, Mr. Sabato said, is characteristic of the Arizona senator, once regarded as a maverick within the Republican Party. “That’s McCain. He’s not going to let this go, even though it’s in his own interest to put the immigration issue to bed,” he said.