Emily Cain supports mandatory background checks before all firearms purchases. Troy Jackson doesn’t.

It’s another difference between the Democrats running for the nomination to the 2nd congressional district seat.

If Cain, an Orono state senator, wins the June 10 primary over Jackson for the seat, outside groups supporting gun rights, led by the National Rifle Association, could spend a lot of money boosting the winner of the Republican primary, either Kevin Raye or Bruce Poliquin, who have been touting pro-gun stances.

Jackson has consistently gotten perfect voting scores and endorsements from the NRA, which hasn’t scored Cain well in the Maine Legislature over the years. Some of the lower marks have been because of Cain’s support of mandatory background checks before gun purchases, including private sales.

So Jackson, the Maine Senate majority leader from Allagash, would be insulated entirely from attacks from pro-gun groups, which normally lean Republican.

There’s precedent for that in Maine: The NRA endorsed Democratic U.S. Rep. Mike Michaud’s in 2012 over Raye. Both have gotten high marks from the group, but Michaud has been routinely endorsed by them over the years.

Federally, Michaud and Maine’s U.S. senators, Republicans Susan Collins and independent Angus King, have questioned how background checks could be applied to private sales, a key piece of President Barack Obama’s gun-control agenda that polls well nationally and in Maine, with nearly 90 percent of surveyed Mainers supporting them in a poll last year.

Under federal law, gun dealers now must do background checks on buyers, wherever they sell guns. Private sellers don’t have to do the checks in most states, including Maine. After a national push last year to tighten gun laws after mass shootings in Colorado and Connecticut, Maine’s gun laws remained practically unchanged.

Here, even a bill that would have encouraged background checks by instituting penalties if private sellers were discovered to have sold guns to people prohibited from having them, such as felons, was rejected by Republican Gov. Paul LePage.

Cain supported that bill; Jackson didn’t.

In an interview, she said she is a staunch supporter of mandatory background checks, even though it may hurt her in the general election among some voters.

“I find being straightforward with people means a lot,” Cain said. “I can look people straight in the eye and say I support Maine gun owners, but I also support background checks that will reduce gun violence.”

But Jackson said she is “going both ways on that issue” by saying she supports background checks and gun owners. He said he is open to considering mandatory checks, but he hasn’t seen a good plan and they may be difficult to implement in rural Maine, where there is a longstanding sporting culture.

“I think in Maine, we’ve had a great culture of people explaining the importance of firearms safety and what guns are for,” he said.

On other issues, Jackson and Cain have similar stances. For example, they are both wary of another Obama idea: banning assault weapons. The two candidates said they worried such a ban could impact guns used for hunting.

David Trahan, the executive director of the Sportsman’s Alliance of Maine, which works closely with the NRA, said his group won’t weigh in on the race at least until the general election.

Cain is “a reasonable lady and very smart and articulate on the issues,” and she is with his group on many issues, he said. However, he said that Jackson is “definitely a clear-cut supporter of gun rights and sportsmen.”

Michael Shepherd — 370-7652mshepherd@centralmaine.comTwitter: @mikeshepherdme