Maine Sen. Susan Collins wants the Senate to strike a provision in the tax reform bill that would repeal the individual mandate because she fears it will cause what amounts to a tax increase on some families.

Speaking on CNN’s “State of the Union,” Collins, a crucial Republican swing vote in the Senate, said the measure, which would essentially cripple the Affordable Care Act by removing one of its key pillars, should be removed from the Senate’s version of the bill.

“I don’t think that provision should be in the bill,” she said. “I think the Senate should follow the lead of the House and strike it.”

While repealing and replacing Obamacare has been on congressional Republicans’ to-do list for years, the party has failed to accomplish that goal since taking control of both chambers of Congress and the White House.

However, the latest attempt to fulfill that long-held campaign promise is coming at a time when Republicans want to accomplish another major goal in tax reform. That has some Republicans like Collins and Alaska Sen. Lisa Murkowski feeling nervous, and that would put tax reform just one Republican nay vote away from failing.

Collins said the measure must be taken out of the bill because it will end up causing families who have healthcare through the Affordable Care Act to pay more for their insurance.

“The fact is that if you do pull this piece of the Affordable Care Act out, for some middle-income families, the increased premium is going to cancel out the tax cut that they would get,” she said.