Sen. Bernie Sanders warned that a growing number of Americans were losing faith in the political system at a New Hampshire site that often hosts presidential primary debates.
But the Vermont senator said is "many, many months" away from deciding on a White House run.
Liberal independent Sanders, 72, covered a raft of issues in an hourlong speech before taking questions from an audience of about 220 people at Saint Anselm College's New Hampshire Institute of Politics in Manchester, New Hampshire.
"What exists all over America today is that millions and millions and millions of people - working people, low income people, young people - they look at the political process and they say, 'Not for me,'" Sanders said in a speech that touched on the widening wealth and income gap in the United States, national security, health care and climate change.
"There are a lot of angry people out there."
Earlier in the week, Sanders told his hometown Burlington Free Press newspaper that if he were to run for president in 2016, it would be important to perform well in the neighboring New Hampshire's first-in-the-nation nominating primary.
On Saturday he said he still had "plenty of time" to make up his mind on whether to run.
"We're giving thought about it, but we've got many, many months," he said in an interview.
Sanders would face an uphill battle were he to seek the Democratic nomination or run as an independent. Polls show former Secretary of State Hillary Clinton, who has not yet said whether she will run in 2016, as the undisputed front-runner with about five times the support of Vice President Joe Biden, her closest potential challenger.
High school history teacher Branden Grant, 27, said he drove 100 miles (160 km) from Pomfret, Connecticut, to hear Sanders speak.
"He's very authentic and sticks to his word and fights the good fight," Grant said. "I like what Bernie says."
But Richard Polonsky, 68, of Bedford, New Hampshire, said he doubted Sanders would have a shot at the White House.
"I would be surprised if he would have a chance of winning, even though I think he should," Polonsky said. "It's a tough road at this point."
Even Sanders had more immediate goals, urging voters to support Democratic candidates in the 2014 Congressional election, to help the party he is most closely allied with hold its 55-43 majority in the upper chamber.
"The first thing we have to do is make sure the Republicans do not gain control over the Senate," said Sanders, who is not up for re-election this year. "I'll be working very hard on it." (Editing by Scott Malone and Gunna Dickson)
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