Iraq and Afghanistan show little interest in getting involved in Syria.
"I don't believe we're going to war, I just don't believe that,'' Kerry told the House Foreign Affairs Committee.
Kerry told the committee that he believed Obama would address the nation on Syria in the next few days. The president returns home Friday night.
Few, if any, members of Congress dispute the Obama administration's claim that Assad was responsible for the chemical weapons attack.
But many Republicans and Democrats in the House question why the U.S. should get involved now in a Syrian civil war that has killed an estimated 100,000, displaced millions and is in its third year. The chamber's most powerful Republicans, House Speaker John Boehner and Majority Leader Eric Cantor, have expressed support for military action, but others in their party remain reluctant or opposed.
Days from a vote, an Associated Press survey of senators found 34 of its 100 members supporting or leaning toward military action, 26 opposed or leaning against and 40 undecided.