* White House denies comment was aimed at Obama
* Obama says Bush policies have strengthened Iran
* Bush recalls Nazi march into Poland (Adds details on previous U.S.-Iran talks, paragraphs 15-16)
By Matt Spetalnick
JERUSALEM, May 15 U.S. President George W. Bush on Thursday decried his critics' calls for negotiations with Iranian President Mahmoud Ahmadinejad as comparable to the "appeasement" of Adolf Hitler before World War Two.
Bush's comment in a speech to Israel's parliament was widely interpreted as a swipe at Democratic presidential front-runner Barack Obama, who has advocated talks without preconditions with leaders of such hostile nations as Iran and Cuba.
Though Bush did not name names, Obama quickly issued a blistering response accusing the president of launching a "false political attack."
But the White House denied Bush was referring to the Illinois senator when, drawing parallels to the rise of Nazi Germany in the 1930s, he denounced those he said had urged him to talk to "terrorists and radicals."
Bush's rebuff to his critics also followed a Middle East visit by former President Jimmy Carter, who met Hamas leaders shunned by Israel and Washington and urged efforts to draw the militant group into the Israeli-Palestinian peace process.
Bush used his speech to the Israeli Knesset to ratchet up his rhetoric against Iran, saying Washington stood by the Jewish state in opposing Tehran's "nuclear weapons ambitions."
But his words also resonated in the presidential campaign, which has increasingly overshadowed him in his final year in office as the Democratic candidates have sharpened criticism of his foreign policy, including the unpopular war in Iraq.
Bush, who has refused any contact with Ahmadinejad, said the Iranian president "dreams of returning the Middle East to the Middle Ages and calls for Israel to be wiped off the map," and lumped him together in an anti-Israel camp with Hamas, Hezbollah and Osama bin Laden.
"Some seem to believe that we should negotiate with terrorists and radicals, as if some ingenious argument will persuade them they have been wrong all along. We have heard this foolish delusion before," Bush said.
"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 added.
Ahmadinejad has come in for international criticism for saying that Israel should be "wiped off the map" and questioning whether the Nazi Holocaust that killed 6 million Jews actually took place. Iran also backs Hamas, whose charter calls for Israel's destruction.
Obama made clear he saw Bush's remarks as an attack on him. "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," he said.
"It is time to turn the page on eight years of policies that have strengthened Iran and failed to secure America or our ally Israel," he added.
"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."
Despite Bush's comments, his administration has directly engaged Iran both on stabilizing Afghanistan after the toppling of the Taliban regime in 2001 and, more recently, to try to quell the violence in Iraq.
The administration also has a standing offer to talk to the Iranians about a wide range issues and to provide economic and other incentives if Tehran first agrees to suspend its uranium enrichment program. Iran has so far spurned the offer.
Iran has been a central issue in the presidential campaign, with Republican candidate John McCain frequently accusing Tehran of sending explosive devices into Iraq used to kill U.S. and Iraqi soldiers.
Obama, vying with Hillary Clinton for the Democratic nomination, has had trouble connecting with Jewish voters, and has struggled to counter doubts raised by critics about his commitment to Israel. McCain has said Hamas favors Obama, who would be America's first black president.
"The speech was not about '08 politics," White House spokeswoman Dana Perino told reporters when asked whether Bush had been referring to Obama.
Bush has led an international campaign to isolate Tehran diplomatically over its nuclear ambitions. He says there is a danger that Iran will use nuclear technology to build a bomb. Tehran says its program is for peaceful civilian purposes.
Bush has accused Iran of fomenting violence against Israel by Palestinian militants, of using Hezbollah to try to destabilize Lebanon's elected government and of arming and training Shi'ite militias in Iraq. (Editing by Andrew Roche and David Wiessler)