WASHINGTON (Reuters) - Democrats erupted in outrage on Thursday after President George W. Bush suggested a pledge by the party's presidential front-runner Barack Obama to meet Iran's leader was akin to appeasement of Nazi Germany.

Bush's comments, made in Jerusalem to the Israeli parliament during celebrations for Israel's 60th anniversary, stirred up the campaign for the November election and prompted Obama to accuse him of engaging in "the politics of fear."

"Some seem to believe we should negotiate with terrorists and radicals, as if some ingenious argument will persuade them they have been wrong all along," Bush said.

Without mentioning Obama by name, Bush compared "this foolish delusion" to the prelude to World War Two.

"As Nazi tanks crossed into Poland in 1939, an American senator declared: 'Lord, if only I could have talked to Hitler, all of this might have been avoided.' We have an obligation to call this what it is -- the false comfort of appeasement, which has been repeatedly discredited by history," he said.

The United States entered the war more than two years after the German invasion of Poland when Japan attacked Pearl Harbor in Hawaii in 1941.

Bush, who has generally avoided talking about the campaign to elect a new president in November, drew a sharp response from Obama, the first-term Illinois senator who is close to defeating rival Hillary Clinton for the Democratic presidential nomination.

Obama maintains he would be willing to meet with leaders of hostile nations like Iran, Syria and Cuba. He argues the United States blundered by refusing to talk to them.

'FALSE ATTACK'

"It is sad that President Bush would use a speech to the Knesset on the 60th anniversary of Israel's independence to launch a false political attack," Obama said.

"George Bush knows that I have never supported engagement with terrorists, and the president's extraordinary politicization of foreign policy and the politics of fear do nothing to secure the American people or our stalwart ally Israel," he said.

Republican John McCain, who has clinched his party's presidential nomination, did not repeat the word "appeasement" when asked about Bush's comments as he campaigned in Ohio.

But he did criticize Obama's pledge to speak directly to U.S. foes, particularly Iranian President Mahmoud Ahmadinejad. He said Obama needs to explain why he would talk to him.

"It shows naivete and inexperience and lack of judgment to say that he wants to sit down across the table from an individual who leads a country that says that Israel is a 'stinking corpse,' that is dedicated to the extinction of the state of Israel. My question is, what does he want to talk about?" McCain said.

Clinton, who has criticized Obama's pledge to meet Ahmadinejad, nonetheless came to his defense.

"President Bush's comparison of any Democrat to Nazi appeasers is both offensive and outrageous on the face of it," she told reporters.

Both Bush and McCain frequently criticize Ahmadinejad for threatening Israel and believe he must be stopped from developing a nuclear weapon, a goal Iran denies.

White House spokesman Dana Perino insisted Bush did not specifically mean to target Obama, saying "there are many who have suggested these types of negotiations with people that President Bush thinks we should not talk to."

A prominent McCain backer, Connecticut independent Sen. Joe Lieberman, a former Democratic vice presidential candidate, said Bush "got it exactly right" by rejecting the idea that "if only we were to sit down and negotiate with these killers they would cease to threaten us."

Many Democrats slammed Bush and pointed out the words of his own defense secretary, Robert Gates, who said on Wednesday: "We need to figure out a way to develop some leverage with respect to the Iranians and then sit down and talk with them."

The Bush administration has talked directly with Iran over the conflicts in its neighbors Iraq and Afghanistan and has offered to discuss a wide range of issues if Tehran agrees to suspend its uranium enrichment program.

"If George Bush believes engagement with Iran is appeasement, the first thing he should do when he comes home is demand the resignation of his own Cabinet," former Democratic presidential candidate John Kerry, an Obama supporter, said.

House of Representatives Speaker Nancy Pelosi, a California Democrat, said Bush's remarks were "beneath the dignity of the office of the president and unworthy of our representation at that observance in Israel."

(Additional reporting by Ellen Wulfhorst, Caren Bohan and Jeff Mason; editing by David Storey and Eric Walsh)