Trio of GOP senators threaten filibuster of gun-control legislation

A trio of Republican senators on Tuesday warned Senate Majority Leader Harry ReidHarry ReidKaine: Dems will use 'nuclear option' if GOP blocks court nominee Five takeaways from New Hampshire Senate debate Democrats pounce on Cruz's Supreme Court comments MORE (D-Nev.) they plan to filibuster any attempts at bringing new gun control legislation to the floor of the Senate.

The move comes just days after Reid announced plans to push forward on a gun control bill which would expand background checks and penalties on straw purchasers.

Sens. Rand PaulRand PaulWhat the 'Bernie Sanders wing of the GOP' can teach Congress GOP senators avoid Trump questions on rigged election How low is the bar for presidential candidates, anyway? MORE (R-Ky.), Mike LeeMike LeeDonald Trump's Mormon PR problem Trump's big worry isn't rigged elections, it's GOP establishment GOP senators avoid Trump questions on rigged election MORE (R-Utah), and Ted CruzTed CruzKaine: Dems will use 'nuclear option' if GOP blocks court nominee Trump knocks Kasich for breaking pledge Democrats pounce on Cruz's Supreme Court comments MORE (R-Texas) argue in a letter to Reid that the proposed bill amounts to an infringement of Second Amendment rights.

"We, the undersigned, intend to oppose any legislation that infringe on the American people's constitutional right to bear arms, or on their ability to exercise this right without being subjected to government surveillance," the senators wrote in the letter, a copy of which was obtained by Fox News.

The senators pledge in the three-paragraph letter they "will oppose the motion to proceed to any legislation that will serve as a vehicle for any additional gun restrictions."

"The Second Amendment to the Constitution protects citizens' right to self-defense. It speaks to history's lesson that government cannot be in all places at all times, and history's warning about the oppression of a government that tries," they wrote.

President Obama and congressional Democrats have been pushing for new gun controls in the wake of the Newtown, Conn. elementary school shooting late last year that left 20 schoolchildren and six educators dead. 

The White House initially proposed that lawmakers consider a renewed assault weapons ban and limits on magazine capacities as part of new gun-control measures. But Reid proceeded without those controversial provisions, acknowledging they did not have enough votes to pass the Senate. The provisions will be offered as an amendment to the legislation.

On Sunday, New York City Mayor Michael Bloomberg announced his political action committee was launching a $12-million ad campaign targeting senators in 13 key states ahead of the vote. 

The White House also said Monday that President Obama would stump in coming weeks in hopes of intensifying pressure on Congress to pass the gun control bill.