(NewsNation) — A new Biden administration immigration program launching Monday will provide legal status to some immigrant spouses of U.S. citizens and provide them a pathway to citizenship.

Under the policy, which President Joe Biden announced in June, many spouses without legal status will be able to apply for something called “Parole in Place,” offering permission to stay in the U.S. and apply for a green card.

The Department of Homeland Security estimates half a million noncitizen spouses and around 50,000 children will be eligible for the program.

While the new program offers a rare opportunity to erase the threat of deportation, there’s concern over whether the program will face legal challenges and if it will survive the presidential election.

What are the program’s eligibility requirements?

To qualify, applicants must demonstrate that their deportation would cause extreme hardship to their American citizen spouse — including financial, emotional and other impacts that separation could bring.

Additionally, they must have been continuously in the U.S. for at least 10 years and have been married to a citizen by June 17 — the day before the program was announced. Applicants must pay a $580 fee to apply and fill out a lengthy application, including a long list of supporting documents proving how long they have been in the country.

They can’t have a “disqualified criminal history or pose a threat to national security or public safety.”

Applicants can apply to the DHS, and if approved, have three years to seek permanent residency. During that period, they can get work authorization.

‘Fixing the system is a top priority’: Harris

While the news has been met with excitement from couples checking where they’re eligible, there’s concern over what would happen if former President Donald Trump is reelected.

On Sunday, Trump attacked Vice President Kamala Harris over her record on the border and vowed to deport millions of immigrants in the country illegally.

“But no comparison of our immigration records would be complete without considering the terrorists that this crazy border czar of ours is letting into America,” Trump said. “We’re going to get (them) out as fast as we can. We’re going to have the largest deportation.”

Meanwhile, Harris says immigration would be one of her administration’s top priorities.

“We know our immigration system is broken, and we know what it takes to fix it, comprehensive reform that includes strong border security and an earned pathway to citizenship,” she said earlier this month.

The Associated Press contributed to this report.