One foreign policy crisis this week brought action from President Obama, another only silence.

As Europe’s economy teetered, Obama held a video-conference call with the leaders of Germany, France and Italy and dispatched his top Treasury official to the continent in the hopes of averting a collapse that could carry the American economy down with it. The poor monthly jobs report released Friday underscored the political stakes for Obama in preventing a European collapse, which would drive down demand for U.S. exports.

But in the furious aftermath of a massacre in Syria that resulted in the deaths of 108 civilians, most of them women and children, Obama has remained quiet. The reticence from a president who has made repairing America’s moral leadership in the region a central premise of his administration, and who delivered a speech from the heart of the Arab world three years ago designed to do just that, has disturbed those pressing for stronger international response to the crisis.

“There was a time when this president looked for opportunities to put his imprint on world events,” said Jon B. Alterman, the Zbigniew Brzezinski Chair in Global Security and Geostrategy at the Center for Strategic and International Studies. “He’s doing less and less of that now, and the reason may have to do with the campaign.”

Any incumbent president hopes for a quiet world during campaign season to avoid the distractions that can upset a successful reelection effort. That is especially true for Obama, who is making his case for a second term in part on the argument that he has been an effective steward of America abroad, concluding its long wars and rejuvenating its alliances.

Although the election will likely be determined by the health of the American economy in a handful of swing states, both Obama and the presumptive Republican nominee, Mitt Romney, have begun to describe the management of foreign affairs as a proxy for presidential leadership.

For example, Obama’s decision in May to produce a campaign video on the anniversary of the operation that killed Osama bin Laden is the clearest example yet of how he has sought to cite foreign affairs as proof of his effectiveness.

When Obama has addressed issues and crises overseas, he has focused on areas that either improve or help preserve his re-election prospects.

In discussing the euro-zone crisis, he highlights the threat it poses to the U.S. economy. He has urged European leaders, most recently in last week’s teleconference call that was a follow-up to the Group of 8 summit at Camp David last month, to take decisive steps to prevent a collapse.

In outlining the end of the war in Afghanistan, he emphasizes the importance of bringing troops home and investing the peace dividend. Polls show that a majority of Americans no longer believe the war is worth fighting.

And in pledging to prevent Iran from developing a nuclear weapon, he describes the need to avert a war with potentially devastating consequences for the oil-rich Middle East, the world economy and an ally with a large political constituency in the United States.

“If during this political season you hear some questions regarding my administration’s support for Israel, remember that it’s not backed up by the facts,” Obama told the American Israel Public Affairs Committee in March. “And remember that the U.S.-Israel relationship is simply too important to be distorted by partisan politics.”

In other areas, some arguably just as urgent, he has been far less visible. Led by the nascent civil war in Syria, those issues carry more political peril than benefit for Obama.

He has not spoken for months about the moribund Israeli-Palestinian peace process he pledged to revive or on the election in Egypt where a candidate from the Muslim Brotherhood, an Islamist movement, will face a former ally of ousted president Hosni Mubarak for the presidency.

He has also said little publicly about the rising violence in Yemen, a new focus of the U.S. counter-terrorism effort, or on Sudan, where fighting along the border with South Sudan threatens a successful independence drive that Obama helped promote.

High-profile presidential involvement in those areas could have the adverse effect of highlighting his inability to resolve ­­problems. As White House Press Secretary Jay Carney noted last week, “There is no question that as mighty as the United States is, that we cannot end all atrocities around the globe.”

As the violence in Syria has spiked in recent weeks, Obama has mentioned the situation only in passing, most extensively before a May 19 meeting of the G8. He said the leaders are “deeply concerned about the violence that’s taking place there and the loss of life.”

But Syria was barely discussed days later when Obama attended the NATO summit in Chicago, where alliance leaders ruled out military intervention in Syria, even as they celebrated the Libya operation of a year ago.

During the teleconference last week, Obama and European leaders spoke about Syria, according to a White House statement. But deputy press secretary Josh Earnest told reporters Friday that “the bulk of the call was devoted to the euro-zone challenges.”

So far, Obama has also ruled out arming Syria’s opposition, arguing that doing so would only inflame an already volatile situation. He has helped organize strict economic sanctions against the Syrian government — and created some new ones of his own targeting those who use technology to carry out mass killings.

By contrast, Romney has called for working with “partners to arm the opposition so they can defend themselves.”

“President Obama’s lack of leadership has resulted in a policy of paralysis that has watched [Syrian President Bashar al-] Assad slaughter 10,000 individuals,” Romney said in a statement last week.

Obama continues to hold out hope that a plan put forward by former U.N. secretary general Kofi Annan will stop the fighting and start a political transition that would usher Assad out.

“It horrifies him,” Carney told reporters this week, adding that Obama, while “taking into account that kind of suffering,” also “has to make practical judgments about what steps we can take, both acting alone and in concert with partners, to bring about the result that we want.”

Obama has left some of the public pronouncements on Syria to his senior advisers.

U.N. Ambassador Susan Rice and Secretary of State Hillary Rodham Clinton have both spoken out against the violence in recent days, and both have blamed Russia for hampering international action against the Assad government.

It was also Clinton, not Obama, who issued a statement condemning the May 25 killing of 108 civilians in the town of Houla. The administration expelled Syria’s senior diplomat in Washington following the massacre but the mass killings have continued.

Romney, a former Massachusetts governor, has no foreign policy experience. But his advisers say they intend to offer a broad critique of Obama’s record abroad, and the candidate has done so in television interviews and through press releases.

Romney has yet to offer a detailed address on the subject this year. His advisers indicated a few months ago that he intended to deliver one by the end of May, but campaign officials said this week that he has yet to schedule one.

Obama last delivered a wide-ranging address on America’s place in the world last fall at the U.N. General Assembly, an annual event.

His advisers say he has also given substantive speeches on the U.S. shift toward Asia during a trip to the region late last year, traveled to South Korea in March, where he spoke about nuclear security and Korean unification, and delivered an important address on food security before the G8 summit last month that was praised by many in the development field.

None of those public remarks held obvious political benefits.

But on his April trip to Colombia, where he attended a regional summit, he brought together foreign policy and domestic politics by promoting U.S. exports and their impact on creating of American jobs.

His last foreign trip before the November election is scheduled for later this month — a visit to Mexico for the G20 summit, where again the economy will be the chief focus.

“That’s what he is going to be elected on — not whether we are exporting democracy or carrying out nation building successfully,” said Marina Ottaway, a senior associate at the Middle East Program of the Carnegie Endowment for International Peace.

She said it is “too risky before the election” for Obama to support military intervention in Syria, and that other parts of the world remain too unpredictable to feature in a campaign.

“What is he going to say about Yemen? That it is a great success? It is not a great success,” she said, citing that case as an example of the ambiguous results the Arab Spring has so far yielded. “That’s what leads to these strange silences that you are noticing from the president.”