U.S. Sen. Susan Collins, R-Maine, said Sunday she does not support a Senate Republican plan to repeal and replace the Affordable Care Act that appears headed for a vote on Tuesday.

Collins, who has opposed her party’s proposals so far because they would entail deep cuts to Medicaid and care for vulnerable citizens, said it isn’t even clear what the Senate will consider on Tuesday.

“We don’t know if we will be voting on the House bill, a second version of the Senate bill or a new version. I don’t think it is a good approach to replacing legislation,” Collins said.

Speaking from Bangor, Maine’s senior senator made her remarks on the CBS News program “Face the Nation,” hosted by John Dickerson. She also discussed the latest developments in the investigation of Russian interference in the 2016 presidential election.

Collins said she still hopes that Republicans can work with Democrats to fix the Affordable Care act and sees signs that Sen. Lamar Alexander, R-Tenn., chairman of the Senate committee that oversees health care, is open to that.

“We could divide this into separate bills and take a look at serious flaws, the most serious of which is the collapse of the insurance markets in several counties throughout the country,” Collins said.

Collins has been a frequent guest on the Sunday morning TV talk show circuit this year. In addition to being a critic of Republican proposals on health care reform, she is a member of the Senate Intelligence Committee, which is investigating Russian meddling and possible ties with the Trump campaign in the presidential election.

Both those issues have been boiling over in the past few weeks. Repeated attempts by Senate Republicans to reform health care have failed and the president’s son, Donald Trump Jr., and son-in-law, Jared Kushner, are scheduled to go before Senate panels this week to talk about their contact with Russians during the 2016 campaign.

Collins also commented on a Washington Post report late last week that Russian Ambassador Sergey Kislyak discussed campaign matters and policy issues important to Russia with Attorney General Jeff Sessions during the presidential campaign when Sessions was a senator.

Collins said the Senate Intelligence Committee will follow any credible allegation in its investigation but so far it is not clear whether the allegation is credible.

“The Russian ambassador is our adversary and they are masters at misinformation. Nevertheless, we have to pursue this further,” Collins said.

She said if the report was accurate, “that is extremely serious. That has the potential of compromising our national security and undermining the safety of those in the intelligence community,” she said.

On Friday, Collins defended special counsel Robert Mueller, who is in charge of the Russia probe, after President Trump appeared to threaten Mueller in an interview with The New York Times on Thursday. She warned the president not to interfere with the investigation.

She reiterated those remarks Sunday.

“I know it is hard, but he needs to step back,” she said.