Senate Judiciary Committee Chairman Patrick Leahy holds a hearing on gun control on March 7. The committee has since passed two bills on guns that are headed to the full Senate.

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This is WEEKEND EDITION from NPR News. I'm Scott Simon.

Colorado's gun control supporters won a big victory yesterday, when the state legislature passed a bill requiring universal background checks for gun sales. The legislation is now headed to Governor Hickenlooper for his signature. In the U.S. Senate, two gun control bills are on their way to a full vote. This week, the Senate Judiciary Committee narrowly approved legislation that would require background checks for nearly all gun purchases. And that bill will likely face stiff opposition in its current version.

But as NPR's Ailsa Chang reports, it's the other proposal, one that bans assault weapons that will likely get the most opposition from lawmakers.

AILSA CHANG, BYLINE: Maybe if zombies attacked, you might need a semiautomatic assault weapon for self-defense. That was one concession Democratic Senator Patrick Leahy of Vermont was willing to make this week when the Senate Judiciary Committee was debating the assault weapons ban. But short of an entire zombie takeover, Leahy says he's always been perfectly satisfied with his .45 caliber at home.

SENATOR PATRICK LEAHY: Even we had people escaping from prison announcing they were going to kill me, I felt pretty comfortable with that.

CHANG: Of course, what's a legislative debate without a few extreme examples. Republican John Cornyn of Texas was also up to the task when he argued: If you take assault weapons away from law-abiding citizens, they'll be outgunned by criminals.

SENATOR JOHN CORNYN: And we're going to give the American citizen a pea shooter to defend themselves with.

CHANG: Pea shooters and zombies, a scenario that seems almost a planet away from the murders in Newtown that launched these legislative efforts. Democrats in favor of the assault weapons ban, like Richard Blumenthal of Connecticut, aren't deluding themselves about the political realities.

SENATOR RICHARD BLUMENTHAL: Realistically, the assault weapon ban faces a very steep uphill climb. But nothing is impossible after Newtown, which so powerfully changed things. We are all different after Newtown.

CHANG: Still, the National Rifle Association has made it clear it will oppose any assault weapons ban. So Blumenthal and his allies say they have greater hopes for a separate provision within the bill, one that bans high-capacity ammunition magazines.

Ailsa Chang, NPR News, the Capitol. Transcript provided by NPR, Copyright NPR.