White House wonders: Should we be harder on Russia than our European allies are being?

But while some of Mr. Obama’s advisers want him to impose sanctions against whole sectors of the Russian economy, the president has decided against it for now, cognizant of the resistance of European nations that have far more at stake economically, officials said.

During internal deliberations, Jacob J. Lew, the secretary of the Treasury, and other officials have argued for caution, maintaining that, while action is needed, more expansive measures without European support might hurt American business interests without having the desired impact on Russia, according to people informed about the discussion.

Mr. Obama has been particularly intent on not getting too far in front of Europe to avoid giving Mr. Putin a chance to drive a wedge in the international coalition that has condemned the Russian annexation of Crimea and destabilizing actions in eastern Ukraine.

“The notion that for us to go forward with sectoral sanctions on our own without the Europeans would be the most effective deterrent to Mr. Putin, I think, is factually wrong,” Mr. Obama told reporters in Asia, where he is traveling. “We’re going to be in a stronger position to deter Mr. Putin when he sees that the world is unified.” He added: “For example, say we’re not going to allow certain arms sales to Russia — just to take an example — but every European defense contractor backfills what we do, then it’s not very effective.”