House Republicans voted on Thursday to weaken the Affordable Care Act's employer mandate—a change that President Obama has previously said he would veto.
The GOP bill passed 252-172, with 12 Democrats joining the Republicans, all of whom voted for the measure.
Under Obamacare, all employers with 50 or more full-time employees will be required to provide health coverage, and the GOP bill would change the law's definition of "full time" from 30 to 40 hours per week.
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Republicans say the change will lift the health law's burden on businesses, which have lobbed heavily for the change. "Not only does it hurt employers faced with unexpected insurance costs, but it prevents them from creating new jobs and threatens them from maintaining their current workforce," said Oklahoma Rep. Tom Cole, a member of the House GOP leadership.
But Democrats point out that the GOP's proposed change would cost $53 billion and prompt 1 million people to lose employer coverage, according to the non-partisan Congressional Budget Office. Health experts believe that's partly because some businesses are expected to move full-time employees to fewer than 40 hours per week to avoid having to comply with the mandate—a shift that would have been less likely under the current threshold of 30 hours per week.
The GOP's bill has also drawn criticism from some conservative opponents of Obamacare as well. "Republican leadership has an odd idea for one of its first big policy pushes of this Congress: a change to Obamacare that threatens to make the law worse," National Review wrote in an editorial.
White House spokesman Josh Earnest said Tuesday that the GOP's "proposed change would actually do a lot of harm, not just to the Affordable Care Act but to a substantial number of workers across the country."