Investors were on edge Wednesday as it seems increasingly likely that the U.S. will lead a military strike against Syria.
All three indexes ended the trading day with gains on Tuesday, but pulled back from earlier highs when leaders in the House of Representatives said they would support President Barack Obama's plan for a strike on Syria.
"Indeed, just how sensitive markets remain to the Syrian situation was shown when U.S. House Speaker John Boehner spoke in support of military action in Syria yesterday," wrote Deutsche Bank analyst Jim Reid in a market report. "This was enough to drive markets lower into the European close and sent the S&P 500 (+0.42% on the day) down 9 points (0.5%) within a matter of minutes."
Obama is seeking approval from Congress to carry out a military strike after saying U.S. intelligence showed that Syria used chemical weapons which killed more than 1,400 people.
Several key Democrats and Republicans have thrown their support behind Obama's plan in recent days, though a number of hurdles must still be overcome before the U.S. can take military action.
While investors are more likely to focus their attention on the situation in Syria Wednesday, there are a number of economic reports that could influence market sentiment.
August auto sales will be reported throughout the day. At 2 p.m. ET, the Federal Reserve will release its Beige Book, a report summarizing economic conditions in the country.
Discount retailer Dollar General ( will report its second-quarter results before the open. )
On Tuesday, H&R Block ( shares were down in after-hours trading after missing analyst expectations. )