Michael R. Bloomberg’s gun control group plans to spend $10 million to help elect Democratic attorneys general this year and in 2026, an investment it says is meant to help protect the rule of law and democracy while President Trump holds the White House.

The group, Everytown for Gun Safety, will back Democratic candidates in 10 competitive states, including Virginia this fall and Arizona, Georgia, Minnesota, Nevada and Wisconsin, among others, next year, according to John Feinblatt, the organization’s president.

The pledged spending from a group fueled by Mr. Bloomberg, the former New York mayor and a Democratic megadonor, is notable because of his apparent reluctance to put his money behind Vice President Kamala Harris last year. He spent months resisting entreaties to donate, though fellow billionaires persuaded him to give $50 million in late October to a nonprofit group supporting her campaign.

Everytown has for years spent money on down-ballot efforts to elect Democratic candidates for state legislatures, particularly in places where gun control measures had a chance of being enacted and where smaller sums of money could have an influence on races.

Mr. Feinblatt said that his group’s push to support attorneys general, which will be called the Everytown Rule of Law Fund, would focus on defending states from actions by the Trump administration more than on serving as an offensive playbook for enacting gun control measures.

Attorneys general “are trying to protect the rule of law,” Mr. Feinblatt said. “They’re trying to protect the things that are in every basic textbook of American democracy.”