President Obama on Wednesday blasted lawmakers for rejecting his push for expanded background checks, a centerpiece of his gun-control agenda, calling it a “pretty shameful day for Washington.”

“They blocked commonsense gun reforms, even while these families looked on from the Senate gallery,” Obama said from the White House Rose Garden, joined by Newtown family members, Vice President Biden and former Arizona Rep. Gabby Giffords. “It came down to politics… They caved to the pressure.”

Earlier in the day, the Senate rejected a bipartisan compromise offered by Sens. Joe Manchin, D-W. Va., and Pat Toomey, R-Pa., by a 54-46 vote. The measure needed 60 votes to make it through the upper chamber.

Obama accused Republicans of caving to the powerful gun lobby, saying such interest groups “willfully lied” about the background checks legislation. However, a few Democrats from red states also voted against the amendment.

The development casts major doubts on Obama’s entire push for new gun restrictions, as background checks were viewed as having the best chance to make it through the Senate. Obama would also like to ban assault weapons and high-capacity ammo magazines, but those ideas were instantly dead on arrival on Capitol Hill.

Still, the president vowed to keep pressing for background checks, calling the defeat “just round one.”

“I believe we are going to get this done,” he insisted. “Sooner or later, we are going to get this right.”