Isakson said the House negotiations fell apart "because quite frankly Heritage Action came out against any compromise and the Republicans could not come together and the Democrats were united and the Republicans had the majority. So when you're in the majority but can't come together you're not going to be able to close the deal."
Groups like Heritage Action and the Senate Conservatives Fund have been vocal proponents of Republicans agreeing to a government funding deal only if that deal also includes a measure defunding Obamacare. A number of Republicans have blamed those groups for pushing Republicans to demand untenable results. Isakson echoed that criticism. He said since Democrats have both the White House and Senate, Republicans couldn't possibly defund Obamacare entirely right now.
Isakson said Republicans should have "gone for a bigger compromise and a bigger reduction in Obamacare rather than the whole enchilada we probably would've been successful with the device tax, the verification of income —with a number of things that we need to do with Obamacare to try and at least fix what's broken with that plan."
The deal Reid and McConnell signed off on includes an income verification provision for Obamacare.