President Biden on Tuesday announced sweeping new protections for hundreds of thousands of immigrants who have been living in the United States illegally for years but are married to American citizens.

Under the new policy, some 500,000 undocumented spouses will be shielded from deportation and given a pathway to citizenship and the ability to work legally in the United States. It is one of the most expansive presidential actions to protect immigrants in more than a decade.

Mr. Biden will celebrate the program during a White House ceremony on Tuesday marking the 12-year anniversary of Deferred Action for Childhood Arrivals, or DACA, which protects people who came to the United States as children from deportation.

The decision comes as Mr. Biden tries to strike a balance on one of the most dominant political issues in 2024. Aware that many Americans want tougher policies on the border, Mr. Biden just two weeks ago announced a crackdown that suspended longtime guarantees that give anyone who steps onto U.S. soil the right to seek asylum here.

Mr. Biden is also expected on Tuesday to detail separate actions that will make it easier for undocumented young people, many of them known as Dreamers, to access work visas.

Almost immediately after he issued that order, White House officials began privately reassuring progressives that the president would also help undocumented immigrants who had been in the nation for years, according to people familiar with the conversations, who spoke on the condition of anonymity to describe private discussions.