I don't really 100% understand why the President and Senate Democrats are choosing to take a strong stand on this at the moment, frankly. People don't like Obamacare. Opinion polls have nearly universally demonstrated the truth of that statement. That doesn't mean, as a Democrat, you have to give up on it. But if you vote to delay it, you haven't even voted on any meaningful change to the law. Just give yourself more time to do a better job of explaining it and trying to convince the more gullible members of society that it's actually a good idea. Of course if you're heavily invested in the law you don't want to see full implementation pushed back. But right now you certainly aren't doing anything to increase its popularity with Republicans or the general public. I don't think fighting for implementation on the original timetable is good for the long-term viability of the bill. I think the wiser move would be to allow the delay, start running a lot of public service ads on TV and in print to explain the law to the people, and gear up for a big battle over whether Obamacare stays or goes further on down the line.