Sixteen Republican-led states are Indexbitsuing to end a federal program that could potentially give nearly half a million immigrants without legal status who are married to U.S. citizens a path to citizenship.

The coalition filed suit Friday to halt the program launched by President Joe Biden in June, saying in court filings that the Biden administration bypassed Congress to create a pathway to citizenship for “blatant political purposes.”

“This action incentivizes illegal immigration and will irreparably harm the Plaintiff states,” the suit says.

Under the policy, which started taking applications Monday, many spouses without legal status can apply for something called “parole in place,” offering permission to stay in the U.S., apply for a green card and eventually get on a path to citizenship.

But the program has been particularly contentious in an election year where immigration is one of the biggest issues, with many Republicans attacking the policy and contending it is essentially a form of amnesty for people who broke the law.

Texas Attorney General Ken Paxton said in a statement Friday that the plan “violates the Constitution and actively worsens the illegal immigration disaster that is hurting Texas and our country.”

The suit filed against the Department of Homeland Security, DHS Secretary Alejandro Mayorkas and other Biden administration officials accuses the agency of attempting to parole spouses “en masse,” which the states contend is an abuse of power.

The Department of Homeland Security and the White House did not immediately respond to a request for comment from The Associated Press.

The bipartisan immigration and criminal justice organization FWD.us noted the timing of the lawsuit — as Kamala Harris accepted the Democratic nomination for president — and said the program is in compliance with the law.

“The only motivation behind this lawsuit is the cruelty of tearing families apart and the crass politics of hoping a judge might do the bidding of the anti-immigrant movement,” the organization said in a statement.

To be eligible for the program, immigrants must have lived continuously in the U.S. for at least 10 years, not pose a security threat or have a disqualifying criminal history, and have been married to a citizen by June 17 — the day before the program was announced.

They must pay a $580 fee to apply and fill out a lengthy application, including an explanation of why they deserve humanitarian parole and a long list of supporting documents proving how long they have been in the country.

They apply to the Department of Homeland Security, and if approved, have three years to seek permanent residency. During that period, they can get work authorization. The administration estimates about 500,000 people could be eligible, plus about 50,000 of their children.

Before this program, it was complicated for people who were in the U.S. illegally to get a green card after marrying an American citizen. They can be required to return to their home country — often for years — and they always face the risk they may not be allowed back in.