The American Medical Association’s new push to unfreeze federal funding for gun research is hitting a wall of resistance in the Republican Party.

In the wake of the mass shooting in Orlando, the nation’s leading doctors group announced Tuesday it plans to “actively lobby” against a nearly 20-year-old budget rule that has prevented federal researchers from studying gun-related deaths.

{mosads}The near-unanimous vote, which took place two days after Orlando shooting early Sunday morning, puts the powerful doctor’s lobby at odds with Second Amendment supporters who have argued that gun-related violence is no different from other violent acts.

Dr. Alice Chen, the executive director of the nonprofit Doctors for America, called the move a “game changer” for the long-standing fight to lift the research restrictions.

“The strength of the AMA’s vast membership, plus that of the over 100 medical and public health groups across the country, will be hard for Congress to ignore,” she said.

But Republicans in Congress, including those in the House Doctors Caucus who are members of the group, are soundly rejecting the AMA’s calls for research into gun-related deaths.

“I don’t particularly see the need for it, quite frankly,” Rep. Tom Cole (R-Okla.), who leads health funding for the House Appropriations Committee, told The Hill on Thursday.

Rep. Michael Burgess (R-Texas), a member of the House Doctors Caucus, said he also opposed the policy change. “Although I’m a member of the AMA, I don’t always agree with the position they take,” Burgess told The Hill on Thursday.   

“It seems to have worked well. I don’t favor changing it,” Burgess said of federal researchers staying away from the issue of guns.

Only one current Republican lawmaker is on record in support: Rep. Bob Dold (R-Ill.), who is among the most endangered House lawmakers this cycle, quietly signed a letter last December from several medical groups that urged GOP leadership to make the change.

Groups like Doctors for America are hopeful they can get more, though many Republicans say they view federally funded gun research as a ploy by the administration to advance stricter laws.  

It’s becoming increasingly unlikely that the gun research will be part of Congress’s response to the Orlando shooting. Cole, the Oklahoma Republican, said GOP leaders are much more likely to boost funding for the FBI to improve background checks.

“Research is good, but unfortunately, this administration has used terrorism despicably to advance their gun control issue. It doesn’t shock me to tears that he might use [Centers for Disease Control and Prevention] research rules to do the same,” Rep. Trent Franks (R-Ariz.) said Thursday.

Democrats this week already forced the GOP-led House Energy and Commerce Committee to vote on the research issue during its markup of a mental health bill. That amendment, from Rep. Tony Cárdenas (D-Calif.), failed on a party line vote of 23-29.

The moratorium on federal gun research stems from a 1997 budget amendment that prohibits federal funds “to advocate or promote gun control” — language that researchers say has had a chilling effect. 

Republicans adopted the so-called Dickey amendment, named after Rep. Jay Dickey (R-Ga.), in 1997 after strong lobbying from groups such as the National Rifle Association. Gun rights supporters have long argued that government agencies use studies to advance gun control, something researchers deny. 

Dickey has since reversed course and is now campaigning to change the wording in the law.

Other gun rights advocates have remained strong in their opposition. Larry Keane, general counsel for the National Sports Shooting Association, said the Centers for Disease Control and Prevention has “misdiagnosed the issue.”

“Our view is that criminal violence involving firearms is a criminal justice,” Keane said in an interview Thursday. “The CDC should focus on its mission, which is addressing diseases and illnesses like cancer and preventing an outbreak of the Zika virus.”

The renewed push for lifting the federal research restrictions began on Tuesday, after the AMA’s policy-making arm, the House of Delegates, decided by voice vote to “actively lobby” on the issue. It also officially declared gun violence to be a “public health crisis” for the first time, over the protest of some members.

American Academy of Family Physicians president, Dr. Wanda Filer, who attended the meeting in Chicago, said she heard “very few nay votes” during the vote.

The resolution had been drafted late into the night on Sunday by a group of young doctors who skipped planned conference festivities to draft it.

It was the second year in a row the AMA’s conference was interrupted by reports of a mass shooting. Last year, the AMA held a moment of silence after the shooting at a historic black church in Charleston, S.C., that killed nine people.

This time, the group voted on nearly a half-dozen emergency resolutions related to gun violence.

Filer said the AMA’s vote adds momentum to the cause that many physician groups, like hers, already supported. 

“Without research and being brave enough to ask the questions, we’re going to have ill-informed, emotional arguments,” Filer said Thursday. “What we’re saying is, we need research.”