Tuesday is also the start of third-quarter earnings season, with results due after the closing bell from aluminum producer Alcoa(AA), along with Yum! Brands(YUM), the parent of KFC, Pizza Hut and Taco Bell.
But investors will likely remain focused on the debt drama playing out in Washington.
"Earnings, I expect they're going to take a backseat as the impasse overshadows," said Peter Cardillo, chief market economist at Rockwell Global Capital. "We're probably going to tread water as we get closer to the Oct. 17 date [a critical debt ceiling deadline]."