BYRON YORK: Dems’ path after Obamacare: Down, down, down.

There were 60 Democrats in the Senate on Christmas Eve 2009, when they voted in lockstep to pass the Affordable Care Act. Soon there will be 46 Democrats in the Senate, or perhaps 47, if Sen. Mary Landrieu manages to eke out a win in Louisiana. In plain numbers, the post-Obamacare trajectory has not been good for Senate Democrats.

The 46 or 47 Democrats in the next Senate are a bit different from the group that passed Obamacare. Sixteen of them took office after the Affordable Care Act was signed into law. They never had to vote for it and have never had to defend voting for it.

Are those post-Obamacare Democrats as strongly opposed to changing the law as their colleagues who voted for it? Or are they possibly a little less personally invested in staving off challenges? It’s a question that will be tested in coming months.

“After [the midterms], the conditions for repeal and replace may be even better than most people think,” writes a Senate Republican aide in an email exchange. “Not only is there a fresh crop of Republicans eager to make good on campaign pledges, but a significant number of Democrats have no particular attachment to the law and may even want to be rid of it as a political issue.”

Well, why should they stick their necks out to protect Obama’s legacy? He certainly won’t do anything to protect them.