That said, I think these types of moves are bad ideas regardless of party (they were popular with my Democratic friends in the early 2000s), for five reasons.
1) It will have unintended consequences. Given the current Democratic coalition, this hurts the Democrats more than it hurts Republicans. In fact, if adopted nationally, these sorts of changes mean Barack Obama would have lost the Electoral College in 2012.
But coalitions are always changing, sometimes rapidly. In 2000, the Democrats’ coalition was broad enough that Al Gore would have won the Electoral College (as well as the popular vote). History isn’t a one-way ratchet, and there’s no reason to believe that 12 years from now, the Democrats wouldn’t benefit from this. …
2) It encourages radical gerrymandering. Gerrymandering doesn’t keep me awake at night as much as it does some people, and its effects are overstated, but at the same time, I don’t think it’s a good thing. And the most likely effect of this scheme is to put enormous pressure on state legislatures to redraw lines as favorably as possible to their parties; we saw some of that pressure in Maine and Nebraska (which have this system) in 2011.