Okay, he said he was going to run for reelection as a Democrat. He's gone back to being an Independent because that is what he was elected as. There is no deviation here. If he runs as an Independent for his next election then yes, he broke his word. I'm pretty sure he will stick to his word if he wants to have any further influence in the party. Reid was willing to put up with his independence and still give him the committee positions he wanted. Schumer won't do the same.