President Barack Obama speaks while flanked by relatives of gun violence victims, in the East Room at the White House, on March 28, 2013 in Washington. President Obama urged Congress to pass measures such as background checks to protect children from gun violence. (Photo by Mark Wilson/Getty Images)

A fiery President Barack Obama pointedly urged Congress to pass gun control legislation in a speech Thursday, repeatedly referring to the shooting of 20 children in Newtown, Connecticut in December, and declaring, “I haven’t forgotten those kids.”

“Less than 100 days ago that happened, and the entire country was shocked. And the entire country pledged we would do something about it, and that this time would be different,” the president said, with mothers of victims of gun violence standing behind him in the East Room of the White House. “Shame on us if we’ve forgotten. I haven’t forgotten those kids. Shame on us if we’ve forgotten.”

He added, “How often do 90 percent of Americans agree on anything? It never happens,” Obama said, referring to broad popular support for expanded background checks for gun purchases, which the president has proposed.

“I ask every American to find out where your member of Congress stands on those ideas. If they’re not part of that 90 percent who agree that we should make it harder for a criminal or somebody with a severe mental illness to buy a gun, then you should ask them, why not? Why are you part of the 10 percent? There’s absolutely no reason why we can’t get this done,” he added.

Putting pressure on Congress

The event marked Obama’s strongest words on gun control since his State of the Union address last month, in which he urged Congress to vote on his ideas to reduce gun violence, which also include an assault weapons ban and a limit on high-capacity gun magazines. Neither of those ideas has gained much momentum in Congress, and Democratic leaders in Congress have focused on background checks as the most far-reaching gun control provision that could pass.

But the background check proposal, despite its wide popular support, is far from guaranteed of getting through Congress, as a bloc of Democrats from conservative states and most Republicans have not declared their support for the provision, which the NRA has suggested is the first step to a national registry for guns. (There is no evidence such a claim is true.)

Senate Majority Leader Harry Reid (D-Nev.) has said “in order to be effective, any bill that passes the Senate must include background checks.” But currently, such a provision does not have the 60 votes to overcome a likely Republican filibuster in Senate or to reach 218 votes in the GOP-controlled House. The Senate will debate gun control when it returns from its recess on April 8.

Can Obama (or Bloomberg) have an impact?

Obama’s words came as New York mayor Michael Bloomberg, perhaps the leading gun control advocate in the country, is running television commercials advocating gun control in 13 states, all of which include a senator who has not yet decided to support background checks. So far, it’s not clear if the ads have swayed any of those politicians. Democratic senators Heidi Heitkamp (N.D.) and Mark Pryor (Ark.), neither of whom has said they will support gun control, have both criticized Bloomberg and suggested their constituents have little interest in the views of the mayor of New York.

It’s not clear how much impact Obama will have either. The White House has pledged it will keep pushing the issue, with the president heading to Denver next week to press his gun control plans.

But Republicans resisted compromising with the president over the so-called sequester a few months ago, letting billions in cuts to the federal government go into effect even as Obama gave numerous speeches criticizing the reductions as damaging to the economy.

Follow Perry Bacon Jr. on Twitter at @perrybaconjr