"I don't know what I'm going to do," he said. "I'm not leaning one way or the other, because I don't have enough information."
Cummings said more than 95 percent of the people who have contacted his office on the issue say they oppose a U.S. attack.
"The people who showed up today," he said, "their message is consistent with what we've been getting on the phone.
"Now it may be that they're more zoned in on it. Maybe a lot of people aren't paying attention to it, so they're not expressing an opinion on it. But I know everywhere I go — shopping centers, gas stations — I have not personally heard one person say we should go, there should be a strike on Syria. Not one."
Perhaps because of that, most Maryland lawmakers — nine of 10 of whom are Democrats — are wading into the debate carefully. Sen. Ben Cardin, a member of the Senate Foreign Relations Committee, was among the first lawmakers to cast a vote on the issue Wednesday. He supported the Senate resolution, which was approved by the committee 10-7. That measure would allow limited military action for up to 90 days and prohibit the use of ground troops.
"America does not want to go to war," Cardin said in a statement. "Congress has no intention of authorizing a war, let alone another long and costly war in the Middle East."
But, he added, "for the sake of America's national security and the stability of the region, we cannot turn a blind eye to this heinous act."
Authorizing military action has won support from both Republican and Democratic leaders in Congress, including House Speaker John Boehner and Minority Leader Nancy Pelosi.
The full Senate is expected to take up the measure early next week. Maryland's other senator, Barbara A. Mikulski, is undecided on how she will vote, a spokeswoman said.
Mikulski, Cardin and Cummings all opposed the 2002 resolution that authorized President George W. Bush to invade Iraq. The only other member of the delegation at that time who is still in office, Southern Maryland Rep. Steny Hoyer, supported the Iraq resolution.
In a statement Wednesday about Syria, Hoyer said Congress "should authorize limited, but decisive, action that leaves no doubt that the use of such weapons will be met with grave consequences."
Rep. Andy Harris, a Baltimore County Republican and the only military veteran representing the state in Congress, is the only Maryland lawmaker who has said that "at this point" he would not support military intervention.
The Iraq war resolution hangs heavily over the Syrian debate, in part because so many lawmakers were later criticized for supporting it. The anti-war protesters Wednesday repeatedly noted that it was Obama who in 2008 criticized his then-rival for the Democratic nomination, Hillary Rodham Clinton, for supporting legislation to invade Iraq.
"The most significant difference … in that long-ago primary is that he had opposed the Iraq war and she supported it," Stewart said. "We've seen this movie before."