If Obama thinks he’s going to win this fight, he is wildly overestimating his own popularity. More to the point, he is overestimating the continued forbearance of people in his own party (and even, eventually, the press). As they begin to realize how badly he is weighing them down, expect to see more Democrats in Congress publicly criticizing the president, hinting that he should back down, and in a few cases—Angus King in Maine, Joe Manchin in West Virginia—considering a defection from the party.
Mitch McConnell has a big piece of leverage to use against them. Under Harry Reid, Democrats weakened the filibuster and a whole host of other rules that used to give some real power to the Senate minority. Either they couldn’t look forward far enough to project the day when they would lose their majority—or they were counting on Republicans to be magnanimous and restore the old rules. McConnell can always promise that yes, he will restore the old system and make life in the minority a lot less difficult, but only so long as Senate Democrats back him up on a few key issues like this one—which are, after all, merely attempts to protect the constitutional prerogatives of the Senate itself. After all, why bother wrangling about Senate rules if Congress has been made irrelevant?
But I’m not sure it will even get to that, because the President has always been pretty free about making petulant threats to bypass his domestic opponents.