ALBUQUERQUE – Senator John McCain pressed his strategy of trying to sow doubts about Senator Barack Obama during the closing month of the campaign by asking a crowd at a rowdy rally here Monday: “Who is the real Barack Obama?’’

That question came in a sharply-worded speech in which Mr. McCain dismissed Mr. Obama as “a Chicago politician,’’ said that the Obama campaign had had to return “$33,000 in illegal foreign funds from Palestinian donors,’’ and sought to raise questions and doubts about Mr. Obama’s background. The speech came as the McCain campaign has opened a series of verbal assaults on Mr. Obama as it tries to turn the page on the financial crisis, which many analysts believe has rallied support to the Democrats. But even as Mr. McCain gave the sharper-edged speech, the stock market was plunging.

In the speech, Mr. McCain repeatedly tried to paint Mr. Obama as a largely unknown, risky choice. “I didn’t just show up out of nowhere,’’ Mr. McCain said to cheers, seeking to draw a contrast with Mr. Obama. He said that “even at this late hour in the campaign, there are essential things we don’t know about Senator Obama or the record that he brings to this campaign.’’

Mr. McCain decried what he called Mr. Obama’s “touchiness every time he is questioned about his record.’’

“For a guy who’s already authored two memoirs, he’s not exactly an open book,’’ Mr. McCain said. “It’s as if somehow the usual rules don’t apply, and where other candidates have to explain themselves and their records, Senator Obama seems to think he is above all that. Whatever the question, whatever the issue, there’s always a back story with Senator Obama. All people want to know is: What has this man ever actually accomplished in government? What does he plan for America? In short: Who is the real Barack Obama? But, my friends, you ask such questions and all you get in response is another angry barrage of angry insults.’’

Mr. McCain complained that “whenever I have questioned his policies or his record, he has called me a liar,’’ even as he accused Mr. Obama of lying about his record.

“Senator Obama has accused me of opposing regulation to avert this crisis,’’ he said. “I guess he believes if a lie is big enough and repeated often enough it will be believed. But the truth is I was the one who called at the time for tighter restrictions on Fannie Mae and Freddie Mac that could have helped prevent this crisis from happening in the first place.’’

Mr. McCain’s return to Washington during negotiations of the financial bail-out bill was criticized by some participants for complicating its passage by injecting presidential politics in the mix, and the bill’s initial demise was widely attributed to the failure of House Republicans to support it. But Mr. McCain faulted Mr. Obama and the Democrats for going slow on the bailout package.

“Today the Dow has fallen below 10,000,’’ he said. “And yet, members of his own party said they felt no pressure to vote for the bill. Why didn’t Senator Obama work to pass this bill from the start? Why did he let it fail and drag out this crisis for a full week before doing a thing to help pass it?’’

The crowd booed mentions of Mr. Obama repeatedly, and several men called out again and again that Mr. Obama was a “liar,’’ and yelled “send him home!”

The Obama campaign responded that Mr. McCain was “angry.”

“On a day when the markets are plunging and the credit crisis is putting millions of jobs at risk, the one truly angry candidate in this race kept up his strategy of ‘turning the page’ on the economy by unleashing another frustrated tirade against Barack Obama,’’ Tommy Vietor, an Obama campaign spokesman, said in a statement.

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