Three conservative senators threatened to filibuster gun control legislation when the Senate takes it up after Easter. “We will oppose the motion to proceed to any legislation that will serve as a vehicle for any additional gun restrictions,” wrote Rand Paul, R-Ky., Ted Cruz, R-Texas, and Mike Lee, R-Utah, in a letter to Senate Majority Leader Harry Reid.

Politico reports:

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.

Lee staged a test vote on the issue during consideration of the Senate budget last week. He tried to amend a point of order against gun control legislation to the budget but fell short. It needed a three-fifths supermajority and failed 50-49, needing 60 votes to pass. But the final tally emboldened Lee, Paul and Cruz because they were so close to a majority and a filibuster takes just 41 votes to sustain.