WASHINGTON — Republicans are seeking to exploit a divide among Democratic leaders over Senator Obama’s pledge to meet rogue leaders personally and without preconditions if he becomes president.

Three prominent Democrats yesterday struggled to defend their party’s likely nominee in his dispute over diplomacy with President Bush and Senator McCain, but each appeared either to misstate Mr. Obama’s position or criticize the idea of meeting unconditionally with the likes of presidents Ahmadinejad or Chavez.

The chairman of the Senate Foreign Relations Committee, Senator Biden of Delaware, said flatly that Mr. Obama had given a “wrong answer” at a Democratic debate last year and indicated that the Illinois senator has since backed off the pledge, but Mr. Obama and his campaign have steadfastly defended his position, including his commitment to sit down with enemy leaders.

The policy question, which has moved into general election territory after figuring prominently in the Democratic primary campaign, centers on Mr. Obama’s response to a debate query last July, when he said he would be willing to meet during the first year of his presidency, without preconditions, with the leaders of five hostile regimes, including Iran and Venezuela. Senator Clinton and other rivals criticized his position, and while Mr. Obama has broadly stuck by his commitment, Mr. Biden yesterday suggested there had been a shift.

“This is a fellow who I think shorthanded an answer that in fact was the wrong answer, in my view, saying I would within my first year,” Mr. Biden said on ABC’s “This Week.” “It implied he’d personally sit down with anybody who wanted to sit down with him. That’s not what he meant. That’s not what he has said since then for the last year or thereabouts.”

Mr. Biden dropped his presidential bid in January, and although he was trying to defend Mr. Obama yesterday, he has remained neutral in the Democratic race.

The issue flared up last week after Mr. Bush told the Israeli Knesset that proposals to negotiate with “terrorists and radicals” amounted to “appeasement” — a statement widely viewed as a shot at Mr. Obama.

The Republican National Committee and the McCain campaign pounced on Mr. Biden’s comments, along with those of two other prominent Democrats, Gary Hart and Harold Ford Jr., who voiced skepticism about Mr. Obama’s position.

“The fact that Senator Obama’s own supporters reject his dangerous and naive foreign policy agenda is yet another indication that he fundamentally lacks the judgment and experience we need in our next commander in chief,” a McCain spokesman, Brian Rogers, said.

Appearing on NBC’s “Meet the Press,” Mr. Ford, the chairman of the Democratic Leadership Council, criticized the idea of meeting with “those that lead rogue nations without some conditions.” Mr. Hart, a former Colorado senator and presidential hopeful, said on CNN’s “Late Edition”: “I don’t think Barack Obama or any other president is going to meet with a head of state without lower-level discussions preceding that. It doesn’t lead to anything.”

Semantics appear to be tripping up the Democrats in the diplomacy discussion. Mr. Obama has said that while there would not be “preconditions” for a presidential meeting with rogue leaders, there would be “preparation,” which could include initial meetings between lower-level officials.

“Barack Obama has been clear and consistent in calling for tough and principled diplomacy without preconditions,” a campaign spokesman, Bill Burton, said. The campaign refused to say, however, whether Mr. Biden or the other Democrats defending Mr. Obama yesterday had mischaracterized his position.

Late yesterday, a spokeswoman for Mr. Biden issued a statement calling the Republican attacks “a distortion” and saying the senator did not intend to criticize Mr. Obama’s position