One of President Donald Trump 's allies in the Senate just took another swipe at Republican health-care plans.

Sen. Tom Cotton, a Republican from Arkansas, cast doubts Tuesday on the GOP's "three-phase" plan to repeal and replace the Affordable Care Act. Cotton, a conservative who said the ACA replacement bill cannot pass the Senate without changes, called talk of a three-step process "political spin."

"There is no three-phase process. There is no three-step plan. That is just political talk. It's just politicians engaging in spin," Cotton told radio host Hugh Hewitt.

The White House and House Speaker Paul Ryan have outlined three phases for their plan to repeal and replace the ACA, also known as Obamacare, and fulfill a key GOP campaign promise. First, the GOP wants to pass the American Health Care Act, the bill working its way through the House that faces opposition from both moderate and conservative Republicans in Congress. Republicans are using budget reconciliation, meaning it only requires a 51-vote majority in the chamber, where the GOP holds 52 seats.

It then would involve administrative actions by the Trump administration and Health and Human Services Secretary Tom Price. That would be followed by more legislation, possibly including a law allowing insurance sales across state lines.

Cotton contended that the second step would face court challenges and likely get hung up in the judicial system. The third phase, meanwhile, could not use the budget reconciliation process the GOP is using for its current bill and would need Democratic support to clear the Senate.

Cotton thinks clearing all of those hurdles is unlikely.

"If we had those Democratic votes, we wouldn't need three steps. We would just be doing that right now on this legislation altogether. That's why it's so important that we get this legislation right, because there is no step three," Cotton said.

Enough Republican senators have opposed the bill in its current form that passage in the chamber seems unlikely. At least 12 GOP senators have already objected to portions of the bill, according to Vox .