President Donald Trump said Wednesday that he is working on plans to close loopholes in the nation’s background check system for gun purchases.

But what exactly he proposes to do still remains a mystery. And, given the president’s history of flip-flopping on gun law proposals, it’s looking unlikely that he will push for meaningful legislation to stem the increasing number of mass shootings in this country. Without Trump firmly on board, Senate Republicans are unlikely to consider significant change — or any change. Which means that gun reform probably won’t be possible until after the 2020 election.

The good news, such as it is, for Democrats is that Trump is handing them a winning campaign issue — if they play it smart and don’t overreach. Democratic presidential and Senate candidates should be calling for universal background checks, reinstatement of the assault weapons ban and imposition of red-flag laws allowing judges to temporarily remove guns from those who are a threat to themselves or others.

Those are reasonable and much-needed policies with strong public support. Democrats should focus on them and not get lost with measures that tax law-abiding gun owners — measures that play into the National Rifle Association’s claims that Democrats want to take weapons from those who use them for hunting and self-defense.

Democrats should remind voters that after the massacre at a Parkland, Fla., high school in 2017 that left 17 dead, Trump voiced support for universal background checks and keeping guns away from mentally ill people. Then, a year later, he threatened to veto background check bills proposed by Democrats and advancing in the House.

They should remind voters that after three massacres in eight days this summer, in Gilroy, Calif.; El Paso, Texas; and Dayton, Ohio, in which 34 people were killed with assault weapons, the president on Aug. 5 called for “strong background checks” and red-flag laws.

But he has yet to provide any specifics on what he’ll support.

Trump’s first loyalty remains with the NRA, which spent $30 million in 2016 to help get him elected. That’s why he spent 30 minutes on the phone with NRA Chief Executive Wayne LaPierre on Tuesday, but there have been no recent reports of his talking to gun law reform advocacy groups. And why, while he said Wednesday that “we’re working on background checks,” he added that “we already have very serious background checks, we have strong background checks.”

Actually, we don’t. Background checks often are not required for purchases from private parties, commonly at gun shows or online. And state laws vary widely as to what gets reported to the national system. As a result, by one estimate, 22% of gun sales bypass the porous system.

Meanwhile, Trump seems very proud of his new talking point: “It is not the gun that pulls the trigger, it is the person holding the gun.” And his other permutation: “Mental health and hatred pull the trigger, not the gun.” It plays nicely with the false notion fostered by the NRA that gun violence is a mental health problem that somehow can be solved with more services for those who are emotionally disturbed.