WASHINGTON -- President Obama was getting his daily economic briefing one recent morning when a fly distracted him. The president swatted and missed, just as the pest buzzed near the shoes of Lawrence H. Summers, the chief White House economic adviser. "Couldn't you aim a little higher?" deadpanned Christina D. Romer, the chairwoman of the Council of Economic Advisers.

Mrs. Romer was joking, she said in an interview, adding, "There are only a few times that I felt like smacking Larry." Yet few laughed in the president's presence.

If the Oval Office incident was meant as a lighthearted moment, it also exposed the underlying tensions that have gripped Mr. Obama's economic advisers as they have struggled with the gravest financial crisis since the Depression, according to several dozen interviews with administration officials and others familiar with the internal debates.