Senate Judiciary Committee Chairman Patrick Leahy said ahead of Obama's presentation that he didn't know whether an assault weapons ban could pass the Senate, but said there are some measures that can, such as improved background checks.
"There are some who say nothing will pass. I disagree with that," Leahy, D-Vt., told students at Georgetown University Law Center. "What I'm interested in is what we can get."
Acknowledging the tough fight ahead, Obama said there will be pundits, politicians and special interest groups that will seek to "gin up fear" that the White House wants to take away the right to own a gun.
"Behind the scenes, they'll do everything they can to block any commonsense reform and make sure nothing changes whatsoever," he said. "The only way we will be able to change is if their audience, their constituents, their membership says this time must be different, that this time we must do something to protect our communities and our kids."
The president was flanked by children who wrote him letters about gun violence in the weeks following the Newtown shooting. Families of those killed in the massacre, as well as survivors of the shooting, were also in the audience, along with law enforcement officers and congressional lawmakers.
"This is our first task as a society, keeping our children safe," Obama said. "This is how we will be judged."
Seeking to expand the impetus for addressing gun violence beyond the Newtown shooting, the president said more than 900 Americans have been killed by guns in the month since the elementary school massacre.
"Every day we wait, the number will keep growing," he said.
The White House has signaled that Obama could launch a campaign to boost public support for his proposals. Nearly six in 10 Americans want stricter gun laws in the aftermath of the Newtown shooting, with majorities favoring a nationwide ban on military-style, rapid-fire weapons and limits on gun violence depicted in video games, movies and TV shows, according to a new Associated Press-GfK poll.