Opponents have initiated legal action to terminate a federal program that potentially offers a pathway to citizenship for nearly half a million immigrants without legal status who are married to U.S. citizens. Sixteen Republican-led states filed a lawsuit on Friday to stop the program established by President Joe Biden in June. The states allege in court documents that the Biden administration circumvented Congress to establish a route to citizenship for “clear political reasons.”

The initiative, which began accepting applications on Monday, enables spouses without legal status to request “parole in place,” allowing them to stay in the U.S., apply for a green card, and eventually work towards citizenship. The program has stirred controversy amid the ongoing election year, with immigration being a core issue. Many Republicans criticize the policy, labeling it as a type of amnesty for individuals who violated the law.

To qualify, immigrants must have resided continuously in the U.S. for at least a decade, pose no security threat or possess a disqualifying criminal record, and have been married to a citizen by June 17 – the day prior to the program’s announcement. Applicants are required to pay a $580 fee, submit a comprehensive application detailing why they merit humanitarian parole, and provide a substantial set of supporting documents demonstrating their duration in the country.

Applications are submitted to the Department of Homeland Security. If approved, applicants have three years to apply for permanent residency, during which they are granted work authorization. The administration estimates that around 500,000 people could qualify for the program, along with approximately 50,000 of their children.

Previously, individuals residing in the U.S. unlawfully faced challenges in obtaining a green card after marrying an American citizen. They could be compelled to return to their home country – sometimes for an extended period – and were consistently at risk of being denied reentry.