Biden program offers legal status to 500,000 immigrant spouses of U.S. citizens. Here's how it works.

President Biden on Tuesday is announcing a large-scale immigration program that will offer legal status and a streamlined path to U.S. residency and citizenship to roughly half a million unauthorized immigrants married to American citizens.

The Department of Homeland Security policy will allow these immigrants to apply for work permits and deportation protections if they have lived in the U.S. for at least 10 years and meet other requirements, senior administration officials said during a call with reporters.

Perhaps most importantly, however, Mr. Biden's move will unlock a path to permanent residency — colloquially known as a green card — and ultimately U.S. citizenship for many of the program's beneficiaries. The policy, if upheld in court, would be the largest government program for undocumented immigrants since the Obama-era Deferred Action for Childhood Arrivals (DACA) initiative, which currently shields 528,000 so-called "DREAMers" who were brought to the U.S. as children from deportation.