James Bennet, the editorial page editor of The New York Times, said on Thursday that he would recuse himself from any involvement in opinion coverage of the 2020 presidential election, after his brother, Senator Michael Bennet of Colorado, announced his candidacy for the Democratic nomination.

The move by James Bennet, who is considered a contender to succeed Dean Baquet as The Times’s executive editor, was long anticipated. Michael Bennet has served for a decade in the Senate and had earlier signaled interest in a presidential bid.

It is unusual for the chief of a newspaper’s Opinion section to withdraw from a topic that is certain to dominate the global news conversation over the next 18 months. Mr. Bennet’s self-imposed moratorium applies to Op-Eds, columns, editorials and other opinion articles related to the presidential candidates or major issues in the campaign.

The Times said Mr. Bennet’s deputies, Kathleen Kingsbury and James Dao, would share responsibilities for all political coverage in their department. The arrangement is expected to last as long as Michael Bennet is an active candidate in the race.