Rebelling against their leaders, four House Republicans on Wednesday signed onto a "discharge petition," giving Democrats the 218 signatures needed to force a vote on a three-year extension of the Obamacare subsidies that are set to expire for millions of Americans on Dec. 31. If the enhanced premium tax credits expire, as is expected, insurance costs are projected to double, on average, for about 22 million Americans who get their coverage through Obamacare. The discharge petition, led by House Minority Leader Hakeem Jeffries, D-N.Y., has all 214 Democrats on board.