Photo: Curtis Compton / Associated Press

WASHINGTON — Sen. Kamala Harris laid out a series of steps Monday night that she would take to try to reduce gun violence if Congress fails to act in her first 100 days if she’s elected president — without having to seek congressional approval.

They include a plan to use executive authority to expand the federal requirement to conduct background checks to more gun sellers, a high priority of gun safety advocates who say loopholes in background-check laws allow too many weapons to fall into the hands of criminals or people who are unstable.

Harris, D-Calif., announced the outlines of her plan in a town hall on CNN in New Hampshire. Her campaign said it would release fuller details Tuesday.

In response to a question from a student in the audience, Harris said no child should have to go through shooting preparedness drills in their schools, and for too long Washington has “failed to have the courage to act.”

“There are people in Washington, D.C., supposed leaders, who have failed to have the courage to reject a false choice, which is just you’re either in favor of the Second Amendment, or you want to take everyone’s guns away.”

The proposal follows policy rollouts from Harris focused on bolstering and expanding the middle class, including one to raise teachers’ pay and a tax credit to help working families afford housing.

On guns, Harris said she would expand the legal definition of a “gun dealer” to apply to anyone who sells at least five firearms a year for profit. As dealers, they would be required to conduct background checks of prospective buyers.

Harris said such a change could be accomplished through a regulation issued by the federal Bureau of Alcohol, Tobacco, Firearms and Explosives. Mostly Democratic efforts in Congress in recent years to expand the background-check requirement have failed to pass.

Harris would also revoke licenses for manufacturers and dealers who “willfully violate the law,” and have federal authorities pursue “egregious” violators in court. Fines generated from such cases would help fund mental health and violence intervention programs.

Harris would reverse President Trump’s narrowing of the definition of “fugitive from justice” to mean anyone with an outstanding arrest warrant. People classified as fugitives are not allowed to buy guns. She would also close the “boyfriend loophole” to prevent anyone convicted of domestic violence from buying firearms.

She said she would also throw her administration’s support behind several measures that must go through Congress to become law. Those include legislation re-establishing a version of the assault-weapons ban that expired in 2004, a prohibition on high-capacity magazines, a bill requiring broader background checks, a ban on those convicted of hate crimes from buying guns, and making firearms trafficking a federal crime.

Harris is not the first Democratic presidential candidate to weigh in on gun control. Rep. Eric Swalwell, D-Dublin, has sought to position himself as a gun-safety-focused presidential contender, and other candidates have spoken about the need for new laws. Swalwell has also proposed a national assault-weapons buyback program to get such guns off the streets.

But Harris’ plan focuses more than others on what the president can do beyond calling for Congress to act.

“This is an informed, original approach that I think is really ... at least for the time being, going to set the bar for who’s most focused on the issue of gun safety,” said Peter Ambler, executive director of Giffords, the anti-gun-violence group founded by former Rep. Gabrielle Giffords, D-Ariz., after she was gravely wounded in a shooting at a district event. The group consults with any politician interested in gun safety, and has not made an endorsement in the presidential race.

Democrats have made preventing gun violence an increasingly high priority, including passing St. Helena Rep. Mike Thompson’s comprehensive background check legislation in the House shortly after taking the majority.

For years, the gun-rights lobby, including the National Rifle Association, had the political upper hand, but in the 2018 midterms, a raft of candidates running on promoting gun safety won swing congressional races. Bolstered by a wave of young activists pushing for action after 17 people were shot to death last year at a high school in Parkland, Fla., gun control has become a more politically salient message.

Harris has long worked on the issue of gun violence, including backing a California law to microstamp guns in her time as San Francisco district attorney. She also backed a bill in 2004 that would have banned gun shows at the Cow Palace — something that will happen starting in 2020.

Tal Kopan is The San Francisco Chronicle’s Washington correspondent. Email: tal.kopan@sfchronicle.com Twitter: @talkopan