Taking a rare sidestep from neutrality, the union representing more than 51,000 stage actors and managers across the United States announced Monday its endorsement of the Democratic presidential ticket of Joe Biden and Kamala D. Harris.

Kate Shindle, president of Actors’ Equity Association, said in an interview that it was the candidates’ alignment with the organization’s platform — including on health care and gun control — that compelled the union to endorse a candidate for president for only the second time in its 107-year history.

The last time was in 2016, when it broke with tradition to back Hillary Clinton’s run for the presidency, also opposing Donald Trump. The union, whose members appear on Broadway, off-Broadway and in regional theaters across the nation, also endorsed two winning Democratic gubernatorial candidates in the midterm elections in 2018: Gavin Newsom of California and J.B. Pritzker in Illinois. But it does not anticipate additional endorsements this year, Shindle said.

“Vice President Biden understands that the arts are a critical driver of healthy and strong local economies in cities and towns across the country,” she said in a statement prepared for the announcement. “He will also be an ally who can help us build a stronger and more inclusive country by championing the rights of workers in every sector, including the arts.”

Shindle added that the organization — now struggling with the impact of a pandemic that has idled much of its workforce from coast to coast — is intensifying its political activity this fall, in the effort to elect Biden. The former vice president’s campaign is arranging to have phone banks available to members of the actors’ union, which has vowed to make at least 5,000 calls for his candidacy.

Many of the union’s stepped-up advocacy efforts this year have concerned legislative responses to the coronavirus pandemic and the shutdown of theaters. Its activism, for instance, around the proposed Heroes, or Health and Economic Recovery Omnibus Emergency Solutions Act, has been manifold. The act would provide an additional $3 trillion in stimulus funds, including money to expand unemployment benefits. The union reports that its members have written more than 57,000 emails and made more than 3,000 phone calls to Congress on behalf of the measure.

The public visibility and performance skills of American actors could no doubt be put to effective use in a campaign, which adds to the value of an endorsement. Asked if she might campaign for Biden and Harris, Shindle said she would be willing to hit the road — a terrain she knows well. Among other things, she is a former Miss America.