WASHINGTON (AP) — Democrats are taking an aggressive stance in their drive to curb firearms, announcing that the gun control legislation the Senate debates next month will include expanded federal background checks for gun purchasers.

Senate Majority Leader Harry Reid said Thursday that the measure will include tougher laws and stiffer sentences for gun trafficking and increased school safety grants.

Closing background check loopholes will be the core of the legislation, just as it was the cornerstone of President Barack Obama’s proposals for stemming gun violence following the December slayings of 20 first-graders and six staffers at Sandy Hook Elementary School in Newtown, Conn.

Including expanded checks in the gun legislation signals that Democrats feel they can win bipartisan support for the measure or are happy to dare Republicans to reject the entire gun-control package and face political consequences in next year’s elections.

Reid, D-Nev., said he hoped a trio of senators would craft a bipartisan background check compromise. If not, he said, senators would consider a stricter version that allows fewer exemptions approved by the Senate Judiciary Committee on a party-line vote.

“This moves the ball forward on gun safety in the Senate,” said Sen. Chuck Schumer, DN. Y., one of the senators searching for a background check deal.

Schumer said he hoped an accord could be ready when the Senate returns from its upcoming two-week spring break. Moderate Sens. Joe Manchin, D-W.Va., who has an A-rating from the National Rifle Association, and Mark Kirk, R-Ill., are also involved.

The background check system is aimed at preventing criminals and others from acquiring firearms. It currently applies only to sales by federally licensed gun dealers, not private transactions at gun shows or online.

The fate of the overall legislation remains uncertain, with Democrats all but sure to need Republican support for it to survive. Action would then shift to the GOP-run House, where leaders have shown no taste for expanding background checks for private purchases.