As Debate Looms, Romney Calls Obama Weak on Foreign Policy

* Romney says Obama has left US "at the mercy of events"

* He faults Obama on Iran, Egypt, Libya, Arab Spring

* Obama and Romney prepare for Wednesday's first debate

* High stakes await the candidates in Denver

By Sam Youngman

BURLINGTON, Mass., Oct 1 (Reuters) - Republican challenger Mitt Romney launched a fresh attempt on Monday to paint President Barack Obama as weak on foreign policy, saying he has let U.S. leadership atrophy, while the two candidates prepared for Wednesday's critical first debate.

Romney's aides said the weak U.S. economy remains his chief priority heading into the Nov. 6 election, but the Democratic president's handling of national security is also fair game.

This line of attack could be tricky for Romney, who drew heavy criticism for a hasty initial reaction to upheaval in Egypt and Libya last month in which the U.S. ambassador to Libya was killed in an attack along with three other Americans.

Romney is under enormous pressure for a good performance at Wednesday night's debate in Denver. His campaign has looked shaky since a leaked video emerged two weeks ago in Romney says 47 percent of Americans are "victims" who depend on government, do not pay federal income taxes and are unlikely to support him.

Seeking to take some of the shine off Obama's national security credentials, which include the 2011 killing of al Qaeda leader Osama bin Laden, the Romney team is aiming to portray Obama as overseeing a period of American decline in the world.

In a Wall Street Journal opinion article, Romney accused Obama of being too timid in responding to the Syrian civil war, the election of an Islamist president in Egypt, the attack on the U.S. mission in Libya, and the threat of Iran developing a nuclear weapon it could use against U.S. ally Israel.

"These developments are not, as President Obama says, mere 'bumps in the road.' They are major issues that put our security at risk," Romney wrote.

"Yet amid this upheaval, our country seems to be at the mercy of events rather than shaping them. ... And that's dangerous. If the Middle East descends into chaos, if Iran moves toward nuclear breakout, or if Israel's security is compromised, America could be pulled into the maelstrom," Romney wrote.

Taking aim at Obama on national security may be an uphill battle for Romney. Reuters/Ipsos poll findings show Americans believe Obama has a better plan to deal with the threat of terrorism by 43 percent to about 30 percent for Romney.

Romney continues to trail Obama in opinion polls five weeks before the election. Obama maintained a lead of 5 percentage points - 46 percent to 41 percent - in a Reuters/Ipsos daily tracking poll released on Monday. Last Thursday, the same poll showed Obama with an advantage of 7 percentage points.

"I think even our opponents will agree right now that this is a closing race," Romney senior adviser Kevin Madden said.

A Washington Post/ABC News poll released on Monday showed Obama leading by 11 percentage points among likely voters in nine battleground states where the election likely will be decided, even as the race is essentially tied nationally.

In his Wall Street Journal piece, Romney told Obama to take a harder line with Iran and to back Israel.

"When we say an Iranian nuclear weapons capability - and the regional instability that comes with it - is unacceptable, the ayatollahs must be made to believe us," Romney wrote.

The White House argues that Western sanctions are having a crippling effect on Iran's economy as reflected by its currency losing a quarter of its value against the dollar in only a week.

As part of the Republican attempt to chip away at Obama's foreign policy record, the pro-Romney group American Crossroads released a video that questioned his reaction to the attack last month on the U.S. mission in Benghazi, Libya, in which the U.S. ambassador was killed.

"What did President Obama do on the same day as a terrorist attack on American citizens? He campaigned in Las Vegas. ... President Obama needs to learn: Being president isn't just about being on TV and protecting your job. It's about leadership. It's time for a president who gets it," the video said.

Romney added that Obama "has allowed our leadership to atrophy," has no strategy to encourage a positive outcome from the Arab Spring revolutions, and has alienated Israel.

"By failing to maintain the elements of our influence and by stepping away from our allies, President Obama has heightened the prospect of conflict and instability," he wrote.

Aides said Romney plans to deliver a foreign policy address in the days following the first debate, probably next week.

Wednesday's debate will mark the first time the two candidates will stand on the same stage together in the campaign. Both sides have been working to lower expectations, each calling the other a better debater.

Romney engaged in a session of debate preparation at a Burlington, Massachusetts hotel before flying to Denver for an evening rally. Obama was in the Las Vegas suburb of Henderson working on his own preparations for the debate.

"Governor Romney, he's a good debater," Obama told a rally in Las Vegas on Sunday night. "I'm just okay."

Given Obama's tendency to meander, aides said they have been trying to get the president to give snappier answers to questions and limit the professorial nature of his responses.

Romney's aides have been working to make sure he does not come off as scolding and to encourage him not to quibble about the rules as he did in some debates during the Republican presidential primary battle. (Additional reporting by Jeff Mason; Writing by Steve Holland; Editing by Alistair Bell)