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Republican Senators involved in previous immigration reform efforts assailed President Obama Friday for blaming them for not succeeding in fulfilling his May 2008 promise to "have in the first year an immigration bill that I strongly support and that I'm promoting."

"A promise is a promise," Univision moderator Jorge Ramos challenged the president Thursday. " And with all due respect, you didn't keep that promise."

The president noted that the pledge was made before the economic meltdown, which made other legislation higher priority. He also blamed Republicans, saying, "what I confess I did not expect - and so I'm happy to take responsibility for being naive here - is that Republicans who had previously supported comprehensive immigration reform - my opponent in 2008, who had been a champion of it and who attended these meetings - suddenly would walk away. That's what I did not anticipate."

On the Senate floor Friday, that opponent - Sen. John McCain, R-Ariz. - expressed bewilderment at the charge.

"I was just informed that the President of the United States, while speaking to Hispanic television, alleged that the reason why immigration reform was not enacted in the last four years of his presidency is because the senator from Arizona walked away," McCain said. "Incredible. Incredible statement.

"I'm not often in the business of accusing Presidents of the United States of not telling the truth, but facts are stubborn things," McCain continued. "First of all, it was then-Senator Obama who joined with Senator Kennedy and me when we were doing comprehensive immigration reform, and we pledged that we would take tough votes so that the whole fragile coalition would not fall apart. Instead of doing that, the then-senator from Illinois, Barack Obama, proposed an amendment which would have destroyed the entire coalition we had together and did so without telling Senator Kennedy or me or anyone else, by sunsetting the provisions that called for temporary workers.

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McCain continued, noting that in 2009, invited to the White House, he'd participated in "a conversation with others about comprehensive immigration reform, and the president at that time stated they would be proposing legislation. I told him I'd be glad to examine it and I'd be glad to support any effort for comprehensive immigration reform that I could agree with. Nothing came from the White House. Zero. Not one word. Not one piece of legislation was proposed by the administration."

After the tragedy in Tucson, McCain praised the president for his speech calling for the nation to enter an era of civility and wrote an op-ed in the Washington Post thanking him.

"I was invited over to the White House again," McCain recalled, "when we discussed comprehensive immigration reform. I said, 'I'm ready to sit down with you and move forward on it.' He said, 'Of course.' There was never a word….I still stand ready to move forward with comprehensive immigration reform."

-Jake Tapper and Sunlen Miller