With hopes for new gun-control laws fading on Capitol Hill, President Obama made clear Thursday that the White House views universal background checks as the barometer for victory in the pursuit of new gun restrictions.

Surrounded by mothers, including some whose children were victims in the massacre at Sandy Hook Elementary School, Obama looked to dispel the notion that it was too late for lawmakers to coalesce behind new gun laws.

“Shame on us if we’ve forgotten,” Obama said during a speech at the White House. “I haven’t forgotten those kids. Shame on us if we’ve forgotten . . . We need everybody to remember how we felt 100 days ago and make sure that what we said at that time wasn’t just a bunch of platitudes — that we meant it.”

However, Obama didn’t say whether he thought an assault weapons ban — the most controversial provision of his gun-control recommendations  — should be enacted. Though he made a brief mention of “weapons of war,” Obama focused most of his attention on background checks, the centerpiece of a bill to be debated in the Senate next month.

“How often do 90 percent of Americans agree on anything?” Obama said, hoping to paint those against universal background checks as outside the mainstream.

Majority Leader Harry Reid, D-Nev., stripped the assault weapons ban and a prohibition on high-capacity magazines from the bill soon to be debated in the Senate. Those measures will be included as amendments, virtually ensuring their failure.

And some Republicans were hardly moved by Obama’s call for action on Thursday.

“It is deeply unfortunate that he continues to use the tragedy at Newtown as a backdrop for pushing legislation that would have done nothing to prevent that horrible crime,” Sen. Mike Lee, R-Utah, said in a statement. “This debate is about more than magazine clips and pistol grips. It is about the purpose of the Second Amendment and why our constitutionally protected right to self-defense is an essential part of self-government.”