The analysis from Third Way says those same eight states - Colorado, Florida, Iowa, Nevada, New Hampshire, New Mexico, North Carolina and Pennsylvania - also saw the number of voters who regsterd as Republicans fall, but only by 79,000.
Politico says the implications are big for this year's election:
While the study’s findings will be disturbing to Democrats — party registration declined by 5.2 percent overall in the 8 battleground states — the news isn’t all that promising for the GOP either. Republican registration declined by 0.7 percent in those states over the past four years, despite a competitive presidential primary in 2012.
All of it suggests that independent voters are poised to be an essential constituency this year in a presidential election that shows every sign of being a nailbiter.