Sen. Mike Lee, R-Utah, will offer an amendment to the Democrats’ fiscal 2014 budget resolution that seeks to require a two-thirds majority for the passage of any gun control legislation in the Senate.

The amendment by Lee, a member of the Judiciary Committee who has tea party backing, comes ahead of the biggest floor debate on gun control in nearly two decades. Majority Leader Harry Reid, D-Nev., announced Thursday that he would bring a package of gun-related bills to the floor during the week of April 8, when lawmakers return from their two-week spring recess.

Lee’s amendment, which his office provided to CQ Roll Call, features a broad definition of gun control and seeks to require a 67-vote supermajority threshold for passage of a number of the proposals that are expected to be debated on the floor next month.

The amendment, for example, seeks to require the supermajority for any bill that “prohibits specific firearms or categories or firearms” or “limits the size of ammunition feeding devices,” an apparent reference to the assault weapons ban (S 150) sponsored by Sen. Dianne Feinstein, D-Calif.

It would also require a supermajority for any bill that “requires background checks through a federal firearms licensee for private transfers of firearms,” a reference to a proposal (S 374) by Sen. Charles E. Schumer, D-N.Y., that has been the subject of weeks of bipartisan negotiations and also will be included in the April floor debate.

The negotiations between Schumer and Republicans, including Sen. Tom Coburn of Oklahoma, have stalled on the question of whether records should be kept of private firearm sales. Coburn has raised concerns that such a requirement would lead to a national gun registry, and Lee’s amendment also seeks to address that concern. It would require a supermajority for any bill that “establishes a record-keeping system for the sale of firearms.”

Lee’s amendment is highly unlikely to succeed in the Democratic-led Senate, but one gun-rights group praised it on Friday.

“We would prefer to prohibit any and all gun control, even if it had 100 votes,” Gun Owners of America said in an email to supporters. “But if the Lee amendment is passed, the practical effect will be that gun control can never again pass the Senate.”