As Republican House members gathered in the White House Rose Garden to trumpet their passage of a bill to repeal the Affordable Care Act, many Senate Republicans voiced deep skepticism that it would ever become law—at least in its current form.

As Republican senators announced they were working on their own alternative bill, Sen. Susan Collins (R-ME) weighed in with a lengthy statement criticizing the House version, which she said raises “more questions than answers about its consequences.”

Collins specifically pointed to provisions in the bill that drastically reduce the subsidies some people can receive to buy health insurance on the individual market.

“The House bill’s tax credits do not adequately take into account income levels, or geographical differences in health care costs,” she wrote. “I am particularly concerned about the effect on lower-income people in rural areas.”

Collins also said she had serious concerns about provisions in the bill that would cut funding for special education services and allow states to waive cost protections for people with pre-existing conditions.

“We really need the Congressional Budget Office to assess the impact of the bill on coverage, costs and premiums,” she concluded, throwing subtle shade at her House colleagues for voting on the bill without waiting for the office’s analysis, which is expected to come next week.