Rep. Tom MacArthur, who had a 93 percent favorable rating from the National Rifle Association, has broken with the powerful gun rights lobby and endorsed background checks for all gun purchases in the wake of the Florida high school shooting that claimed 17 lives.

MacArthur, R-3rd Dist., had opposed the proposal in the past, receiving a 0 percent rating from the Brady Campaign to Prevent Gun Violence, according to Project Vote Smart, which tracks lawmakers' positions on key issues.

"Background checks are worthless, unless they cover every gun purchase," MacArthur said Wednesday.

MacArthur's statement came on the same day more than 200 people led by high school students held a protest at his district office in Burlington County.

While federally licensed gun dealers must check every purchaser, no such requirement exists for sales at gun shows or over the Internet.

One of the speakers at Wednesday's protest at MacArthur's office in Burlington County, high school student Galen Ekimov, said he wanted to see the congressman's next move.

"Talking about it is a step in the right direction," said Ekimov, 17, a senior at Shawnee High School in Medford. "Let's see what he does."

President Donald Trump also has called for expanded background checks.

Whether we are Republican or Democrat, we must now focus on strengthening Background Checks! — Donald J. Trump (@realDonaldTrump) February 21, 2018

MacArthur also said Attorney General Jeff Sessions should "issue guidance to states, which have their own background check systems, on ways to bolster their efforts, and make them more universal across the board."

Trump's proposed budget for the 12 months beginning Oct. 1 cuts spending to states to help them update their databases to $61 million from $73 million.

Senate Democratic Leader Chuck Schumer of New York called such cuts "downright dangerous.

The NRA spent more money on politics in 2016 than any other interest group, $55 million, according to the Center for Responsive Politics, a Washington-based research group. Most of that money went to elect Trump and keep Republican majorities in the House and Senate.

Charlene is a @MomsDemand & @Everytown advocate. Randy is a member of the @NRA. I represent both in Congress. I was inspired by my discussion with them and believe we can all come together to make our communities safer by addressing gun violence. pic.twitter.com/UdjsN5a1tx — Archive: Tom MacArthur (@RepTomMacArthur) February 20, 2018

MacArthur, who has received NRA support and describes himself as "a strong supporter of the Second Amendment," supported two measures that would keep some mentally impaired individuals out of the database.

In the first instance, Trump signed legislation overturning the requirement that the Social Security Administration report to the background check database the names of those with mental illnesses who need representatives to handle their disability and supplemental benefit checks.

The rule announced by President Barack Obama was a response to the 2012 Sandy Hook massacre in Connecticut, in which 20 elementary school students were gunned down.

The second measure, pending in the Senate, would prevent the Department of Veterans Affairs from reporting the names of veterans deemed mentally incompetent.

Under the legislation, a judge would have to decide that veterans posed a danger to themselves or others before they could be denied the right to buy weapons.

He also co-sponsored the Concealed Carry Reciprocity Act, which would require New Jersey to honor concealed weapons permits for people who got them in their home state, like they now do for driver's licenses.

In supporting the legislation, which passed the House and awaits action in the Senate, MacArthur cited the case of Shaneen Allen, a single mother of two and gun owner from Pennsylvania who was arrested in October 2013 for carrying a concealed weapon into New Jersey. She was arrested, spent 40 days in jail before making bail, and faced a prison term before Gov. Chris Christie pardoned her.

House Democrats held a sit-in on the House floor in June 2016 to press House Speaker Paul Ryan, R-Wis., to allow a vote on gun safety measures. Ryan refused.

The next year, congressional Republicans adopted new rules to penalize lawmakers who hold similar protests going forward.

U.S. Sens. Cory Booker and Robert Menendez, D-N.J., joined a Senate Democratic filibuster earlier that month to force a vote on expanded background checks. Senate Republicans blocked action on the legislation.

Jonathan D. Salant may be reached at jsalant@njadvancemedia.com. Follow him on Twitter @JDSalant or on Facebook. Find NJ.com Politics on Facebook.