The same trio then faced questions on Wednesday before the House Foreign Affairs Committee, with Royce saying the administration's Syria policy had been adrift for two years.
At the same time, Royce acknowledged there were "no easy answers" on Syria, and attempting to deter chemical weapons use was worth considering despite public skepticism for U.S. military involvement.
Kerry said Obama sought authorization for a response to the use of banned weapons, not a full military intervention.
"We are not asking America to go to war," he said. "We all agree, there will be no American boots on the ground."
In response to a question, Hagel put the cost of the limited response under consideration at "tens of millions" of dollars.
Most of the focus of administration lobbying has been on the House, where opposition by liberal Democrats and libertarian conservatives, as well as the bitterly partisan political environment of the Republican-led chamber, make passage of Obama's authorization proposal uncertain.
House Speaker John Boehner and Cantor, the No. 2 Republican, both have endorsed a U.S. military response, but Wednesday's hearing showed widespread concerns and outside opposition from across the political spectrum.
Polls also show that a majority of Americans oppose a U.S. military strike on Syria.
In the Senate, a Democratic source familiar with Majority Leader Harry Reid's thinking told CNN that Reid is confident any authorization measure will pass his chamber. The source said it is likely 60 votes will be needed to overcome a filibuster, and Reid thinks the votes are there.
Before that, however, lawmakers will hear from the Russian government, which is moving ahead with its efforts to lobby Congress in an attempt to undercut Obama on Syria. Moscow has sent an official request to congressional leaders to meet with them.
"We're planning the visit," a Russian Embassy spokesman told CNN, "We can't tell you the exact time but it will be next week."
Boehner will not meet with the Russians, his spokesman said.