A top Democrat negotiator in the U.S. Senate says that raising the federal age to buy an AR-15-style semi-automatic rifle to 21 is now off the table.

In the wake of multiple recent mass shootings, the junior Democratic senator from Connecticut, Chris Murphy, said that the proposed change to increase the age requirement to buy semi-automatic rifles was dropped in an attempt to solidify support from Republicans in the Senate, Just the News reported.

Any legislative change will require support from at least ten Senate Republicans to overcome a 60-vote procedural hurdle in the 100-member chamber.

Murphy said that the compromise would require adding “additional scrutiny” to 18- to 21-year-olds who try to buy semi-automatic rifles like an AR-15. Murphy didn’t, however, say whether a waiting period would be introduced in lieu of raising the minimum age requirement.

Murphy said, “I think we continue to try to find a path to 60 votes that includes some provision that recognizes these 18- to 21-year-olds tend to be the mass shooters, and that many times, they have juvenile criminal records or past histories of mental health that should prohibit them from buying a weapon.”

The Democratic senator also reportedly thinks there would be some Republican support for raising the age but that there simply will not be enough to meet the 60-vote threshold to circumvent a legislative filibuster.

Murphy also expressed optimism and stated that negotiations have advanced beyond expectations despite Congress being unable to implement further restrictions on the ownership or purchase of private firearms for the past 30 years.

Murphy also said that a federal red-flag law would not be included in a potential legislative proposal. He did, however, insist that that there will be “incentives” for states to pass or strengthen their already existing red-flag flaws. Red-flag laws allow police, teachers, and family members to petition a court to remove weapons belonging to gun owners who are deemed a danger to themselves or others.

The senator suggested that demand for gun control from the constituents of Republican senators will enable the Senate to ultimately pass some form of gun control.

He said, “I think that we can put together a package that will get more than 10 Republican votes, and the reason for that is the demand from their constituents. I’ve never been part of a negotiation that was this serious.”