But Brad Sorensen, director of market and sector research at Charles Schwab, thought that worries about a government shutdown would ultimately be short-lived.
"Investors are becoming a little bit immune to the games that Washington has started to play," Sorensen said. "Investors with a stronger stomach should probably buy the dip."
Stocks, for example, plummeted in the summer of 2011 as lawmakers wrangled about raising the debt ceiling. The market also sagged in October last year before the Presidential elections, on concerns that a divided government would be unable to agree on tax reform. Each time though, backed by the Fed's economic stimulus, the market came back stronger.
After falling 2 percent in October of last year, the Standard & Poor's 500 index rose for seven straight months, gaining 15 percent.
On Tuesday, the Dow closed down 66 points, 0.4 percent, to 15,334. The S&P 500 index fell four points, or 0.3 percent, to 1,697. The Nasdaq composite, however, edged up three points, or 0.1 percent, to 3,768.
Stocks edged lower in early trading, before reversing the losses to move modestly higher by late morning. The gains then fizzled out.
Phone company stocks were the biggest decliners among the 10 industry groups that form the S&P 500. Industrial stocks were the biggest gainers.
Before the market opened, a survey showed that home prices rose the most since February 2006. A revival in housing has been one of the bright spots for the economy.
In another key economic gauge, the Conference Board, a New York-based private research group, said that its consumer confidence index dropped to 79.7 in September, down from August's 81.8.