Maine Sen. Susan Collins said Sunday morning it's "very difficult" to envision herself voting for the latest attempt to overhaul the Affordable Care Act.

"It's very difficult for me to envision a scenario where I would end up voting for this bill," Collins said on CNN's "State of the Union."

Collins has long been viewed as a likely no vote on the legislation that would end up block granting healthcare funding to the states from the federal government.

Collins' statement on Sunday likely means the bill will be dead on arrival in the Senate. Sens. John McCain, R-Ariz., and Rand Paul, R-Ky., have already announced their opposition to the bill.

Collins laid out a number of complaints about the bill that she doesn't believe will be fixed.

"I'm concerned about the impact on the Medicaid program, which has been on the books for more than 50 years and provides healthcare to our most vulnerable citizens, including disabled children and low-income seniors," she said.

"I'm concerned about the impact on costs and coverage. We already have a problem under the Affordable Care Act, with the cost of premiums and deductibles. And finally, I'm very concerned about the erosion of protections for people with pre-existing conditions, like asthma, arthritis, cancer, diabetes, and what it would mean to them."

She added she also has process complaints about how the bill has moved through the upper chamber.

"I am worried about whether [the Congressional Budget Office] has been given enough time to thoroughly analyze this bill, which has been a moving target," she said, "even over the weekend, I was receiving emails suggesting that the sponsors of the bill are still changing the formula. So, it may be difficult for CBO to do the kind of in-depth analysis that it usually does, but that's what I would like to see before making a final decision."