The runoff primary in Alabama for Attorney General Jeff Sessions’s old U.S. Senate seat has unexpectedly pitted the moneyed mainstream of the gun-rights movement, the National Rifle Association, against its ideological hard core, Gun Owners of America and the National Association for Gun Rights.

The NRA has endorsed incumbent Luther Strange, appointed to the post in February after Sessions took the top job at the Department of Justice. So, too, has President Donald Trump, and the conservative GOP establishment.

GOA and NAGR, which oppose virtually all gun laws, back Roy Moore, a former chief Justice of the Alabama Supreme Court and a firebrand with a decades-long career as a far-right provocateur. Moore has also cultivated favorites of the Breitbart-reading fringe like former Governor Sarah Palin of Alaska and Sebastian Gorka, the stridently anti-Islamic former White House official. Political observers have called the race “an iteration of the GOP civil war.”

Trump highlighted Strange’s NRA endorsement in tweets about the race, telling followers that the group’s stamp of approval means “all gun owners should vote for Big Luther. He won’t let you down!” The NRA has pumped a lot of money into the state: it spent $873,790.55 in a single week on advertising and voter outreach on behalf of Strange, exceeding the entire amount spent by all outside groups to support his opponent.

The group has also released an ad for Strange in which a shooter takes aim at targets that highlight its endorsement of “Big Luther.” The spot claims Moore is “soft on gun rights,” but doesn’t get specific.

In an effort to build support for its preferred candidate, the far smaller GOA, which has not spent any money at all on the race, has stressed Moore’s ideological pedigree. Officials for the group have said that Moore must be elected to pass the National Concealed Carry Reciprocity, a bill that would force all states to recognize each other licenses to carry weapons regardless of differences in standards for training or background checks. That legislation has long been gun activists’ Golden Fleece. GOA has expressed disappointment at the lack of visible effort to pass the legislation by House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell.

Earlier this month, in an interview with Breitbart, Moore said Congress should vote immediately on the stalled reciprocity bill. Strange co-sponsored the proposal, but so have 37 other Republican senators. Strange hasn’t made reciprocity a campaign issue.

Moore, who enjoyed a solid if not insurmountable lead in a poll released at the beginning of this week, is attempting to cater to the most engaged gun-rights voters at the grassroots level.

He spoke to a small pro-gun group, ‘Bama Carry, at a Birmingham Chinese restaurant, a far cry from Strange’s large, well-financed campaign events featuring national allies like Trump and Vice President Mike Pence. In early August, the former judge pulled a gun out of his wife’s purse at a local Republican meeting and boasted, “We carry.”