Barack Obama seems to have realized that he dug himself a hole when he promised meetings with no preconditions with Ahmedinejad and other tyrants in the first year of his presidency, during a CNN debate last summer. He now is qualifying his blanket statement.

LAS VEGAS - Barack Obama is distancing himself from expectations he would meet Iranian President Mahmoud Ahmadinejad and taking a more cautious stand on talking to other U.S. adversaries.

With criticism from Republicans turning harsher as Obama moves closer to winning the Democratic nomination battle against rival Hillary Clinton, the Illinois senator has shifted -- but not abandoned -- his position.

"There's definitely been an adjustment in what was initially a pretty categorical position," said Ross Baker, a political scientist a Rutgers University. "As (Obama) has gone around the country campaigning, he has realized he's had to fine-tune his position."

The McCain campaign accuses Obama of backtracking and says that shows he lacks judgment on foreign policy matters.

Baker of Rutgers University said Obama's shift makes sense politically. A meeting with Ahmadinejad would be unacceptable to Jewish voters whom Obama wants to court. Promising unconditionally talks with Raul Castro might be unpalatable to Cuban-American voters, he said.

"There are mid-course corrections in every campaign," Baker said. "It's better for him to make that course correction now than later in the campaign."