DENVER >> When President Donald Trump raised the idea of banning “bump stocks” and curbing young people’s access to gun, gun owners and advocates who helped his political rise talked about disloyalty and desertion.

Trump’s flirtation with modest gun control measures drew swift condemnation from gun groups, hunters and sportsmen who banked on the president to be a stalwart opponent to any new restrictions.

He’s pledging to make schools safer and reduce gun violence after the Florida school shooting. But gun advocates see a weakening resolve from the man they voted for in droves and spent millions to elect.

“Out in the firearms community there is a great feeling of betrayal and abandonment because of the support he was given in his campaign for president,” Tony Fabian, president of the Colorado Sports Shooting Association, said Friday.

The comments highlight how little room the president and his party have to maneuver without angering and activating a politically powerful constituency.

Trump has not made a formal proposal and he spent much of the past week endorsing the notion of arming teachers and school officials, an approach the gun lobby supports.

Just floating proposals that defy the National Rifle Association and other groups drew threats of political retribution and legal action.

The confrontation is set to test whether Trump is willing to risk his political capital to take on a core group few Republicans have challenged.

“The president has a unique ability right now to maybe really do something about these school shootings,” said Rep. Tom Rooney, R-Fla. “Nobody is more popular in my district — and I know in a lot of other people’s districts — than Donald Trump. He’s more popular than the NRA. … So it’s up to him whether or not anything happens with guns.”

After 17 people were killed by a teenager at the Florida school, Trump said that assault rifles should be kept out of the hands of anyone under 21. He endorsed more stringent background checks for gun buyers, and ordered his Justice Department to work toward banning rapid-fire “bump stock” devices.

Gun Owners of America issued an alert earlier this past week urging its 1.5 million members to call the White House and “Tell Trump to OPPOSE All Gun Control!” The organization said anti-gun activists aided by congressional Democrats are trying to convince the president he should “support their disastrous gun control efforts,” the message said. “And sadly, it may be working.”

Michael Hammond, legislative counsel for the Virginia-based group, said the organization doesn’t hesitate to oppose Republican incumbents and candidates whom it deems not sufficiently “pro-gun.” Motivating gun owners to go to the polls — not campaign funding — is the source of the gun lobby’s strength, according to Hammond.

“When they feel gun ownership is threatened, then they’re going to respond as if that’s the pre-eminent issue,” he said.

Paul Paradis, who owns a gun store in Colorado Springs, was enthusiastic about letting teachers carry firearms on campus. But he was incredulous about the notion of outlawing bump stocks and increasing the age requirement for buying a long gun.

“Trump can propose anything he wants but it’s got to get through two houses of Congress and the Supreme Court,” Paradis said.

Colorado has been a test case for the politics of gun control and the ability of gun groups to retaliate against those who vote for it. In 2013, after the Aurora theater shooting was followed by the elementary school shooting in Newtown, Connecticut, Colorado’s Democrat-controlled Legislature passed a package of gun restrictions, including universal background checks and a ban on magazines that hold more than 15 bullets.

Gun control advocates hoped to roll the program out to other states after showing a libertarian, Western state could pass the bills. But then the NRA backed successful recalls of two Democratic state lawmakers who backed the legislation. The momentum ended.

Democrats won back those seats in the 2016 election. Still, the message has lingered: Democrats have not proposed any major gun legislation since the recalls.

There are an estimated 55 million gun owners in the United States, according to a 2016 national survey conducted by Northeastern and Harvard universities.

The NRA, which spent about $30 million in support of Trump’s presidential campaign, is firmly opposed to raising the legal age for the purchase of long guns from 18 to 21.

Trump’s call to restrict bump stocks like the ones used in last year’s Las Vegas massacre triggered outrage among gun owners. The devices allow a shooter’s semi-automatic rifle to mimic a machine gun. The Bureau of Alcohol, Tobacco, Firearms and Explosives is conducting a review to determine whether it can regulate bump stocks without action from Congress.