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But Mr. Obama was not outwardly aggressive toward Mr. Bolton during a Senate confirmation hearing in 2005. In fact, he appeared to approve of the nominee’s overall position that the United Nations was in serious need of reform.

Once in the White House, Mr. Obama’s general deference toward working with the United Nations appeared to shine. During a December 2009 speech in accepting the Nobel Peace Prize, he described the international body as a mechanism “to govern the waging of war.”

The Obama administration worked closely with the Security Council’s permanent members, including Russia and France, on resolutions aimed at deterring North Korea from testing or developing nuclear weapons.

But Mr. Obama has not always held others to the rule of seeking Security Council approval for military interventions. He turned a blind eye, for instance, when France sent troops into Mali this year. The president even authorized U.S. military support for the mission, arguing that U.N. approval was not needed on grounds that Mali’s government had invited the French troops to intervene.

That Mr. Obama had been so eager to work with the Security Council on Syria might be explained, at least in part, by presidential politics.

“In 2011 and 2012, prior to last November’s elections, the U.S. was determined to avoid getting dragged into the Syrian war,” said Richard Gowan, associate director for crisis diplomacy and peace operations at New York University’s Center on International Cooperation.

“The Obama administration was determined to avoid an intervention and, to some extent, Russia’s obstructionism at the U.N. gave the U.S. an alibi,” Mr. Gowan said. “Tussling diplomatically with Russia and China was a sort of good way to avoid action. I think the Security Council did offer diplomatic cover in the run-up to the election.”

But, he noted, Obama administration officials also believed that “Russia would back down or that Assad would be defeated on the battlefield.”

“Until the early months of this year, there was more confidence in the West that Assad would lose the war, and one priority for the U.S. was to keep open some sort of U.N. deal at the end of the conflict,” Mr. Gowan said.

With such a deal, he said, the Obama administration might have lobbied the Security Council to authorize a force of peacekeepers to enter Syria.

Analysts said Democratic and Republican administrations have a history of using — or not using — the Security Council on a case-by-case basis.

“It’s true that in terms of rhetoric the Republicans are more negative toward the U.N.,” he said. “But in fact, both Republican administrations often find the U.N. very useful and Democratic administrations often find it necessary to put the U.N. to one side in a crisis, so it’s hard to reduce overall U.S. attitudes toward the U.N. purely to partisan positions.”