The move to defund Obamacare has been slow to gather support in the Senate. Really slow.Republican Sen. Mike Lee has asked colleagues to sign a letter promising to "not support any continuing resolution or appropriations legislation that funds further implementation or enforcement of Obamacare." Of the Senate's 46 Republicans, just 12 signed the letter when it was released in late July.In the weeks since, one more Republican, Sen. Mike Crapo, has joined the pledge, bringing the grand total to 13.