Next month Senate Majority Leader Harry Reid plans to bring legislation criminalizing the transfer of private firearms to the floor for a vote. The package won’t contain Senator Dianne Feinstein’s assault weapons legislation, but it can be offered as an amendment. Reid’s move to bring new gun control up for a vote has sparked another “Stand With Rand” moment but this time, it’s both Senators Rand Paul and Ted Cruz who plan to filibuster the bill.

Sens. Rand Paul, Ted Cruz and Mike Lee are threatening to filibuster gun-control legislation, according to a letter they plan to hand-deliver to Senate Majority Leader Harry Reid’s office on Tuesday.

“We will oppose the motion to proceed to any legislation that will serve as a vehicle for any additional gun restrictions,” the three conservatives wrote in a copy of the signed letter obtained by POLITICO.

Though they don’t use the word “filibuster” in the letter, the conservatives are leaving no doubt that they would filibuster on an initial procedural question — the motion to proceed.

But what’s the point?

Conservatives are concerned that once that bill reaches the floor, amendments could stiffen restrictions on gun control.

Moreover, they understand that Reid intends to allow liberal amendments that would limit clip capacity and ban certain assault weapons to be offered — even though they would be defeated — to give Democrats a chance to vote on them. For moderate Democrats in competitive states, that amounts to an opportunity to vote no and show allegiance to gun rights.

This is actually a brilliant move by Paul and Cruz. Reid has already had the ability to protect Democrats from voting on the assault weapons ban, but a filibuster on criminalization legislation would force Reid to either try and stop the talking, which will bring attention to gun control efforts of vulnerable Democrats or will be forced to allow a filibuster to continue, preventing a vote on the legislation.

Here’s a list of vulnerable Democrats in 2014:

Sens. Al Franken (D-Minn.), and Kay Hagan (D- N.C.) Sens. Jay Rockefeller (D-W.Va.) and Carl Levin (D-Mich.) Sens. Mark Begich (D-Alaska), Jeanne Shaheen (D-N.H.) and Tom Udall (D-N.M.)

Get the popcorn ready.