Cook Political Report on Friday morning changed its ratings for 20 House seats, predicting that Democrats’ odds of winning those districts has increased now that House Republicans passed a bill to repeal Obamacare.

“Although it’s the first of potentially many explosive votes, House Republicans’ willingness to spend political capital on a proposal that garnered the support of just 17 percent of the public in a March Quinnipiac poll is consistent with past scenarios that have generated a midterm wave,” Cook Political Report’s David Wasserman wrote in a post explaining the ratings changes. “Not only did dozens of Republicans in marginal districts just hitch their names to an unpopular piece of legislation, Democrats just received another valuable candidate recruitment tool.”

He wrote that for some Republicans, backing the American Health Care Act is an “unequivocal political risk.”

Cook Political Report moved three districts from leaning Republican to toss-ups, 11 districts from likely Republican to leaning Republican and six districts from solid Republican to leaning Republican.