Maine Senator Susan Collins is breaking with her fellow Republicans to oppose a key funding plan supporting President Trump’s agenda.

The budget resolution passed by a 51-48 margin over the weekend, and supports beefing up border security, expanding oil and gas drilling, increasing defense spending, and extending Trump’s 2017 tax cuts.

Collins voted against the measure because the House version of the plan includes $880 billion in cuts that will likely have a significant impact on Medicaid.

“The House instruction on $880 billion troubles me greatly because I believe that it would inevitably lead to significant cuts in Medicaid, which would be very harmful to people in Maine and to our rural hospitals and other health care providers,” Collins said.

Senator Rand Paul of Kentucky was the only other Republican to vote against the resolution.

The measure only needed a simple majority of votes to pass, and now heads to the House for further consideration.

It’s already receiving pushback from the conservative Freedom Caucus in the House, and Republican House Speaker Mike Johnson can only afford to lose three votes to ensure its passage there.

Johnson is expected to rely on support from President Trump when the resolution is taken up in the House this week.