A few years ago, when Rand Paul launched into his epic filibuster, Republicans were ecstatic. They applauded, they tweeted #StandWithRand until their fingers bled, they stayed up all night watching, and they cheered until they were hoarse. Back then, there was a Democrat in the White House. Now, there's Donald Trump. Since he's at least nominally a Republican, congressional GOP members saw Rand Paul approach the microphone and the look of dread was obvious.
They wanted their atrocious, deficit-ballooning budget deal to pass, and they hoped it would pass quietly in the dead of night. With Paul holding the floor, that wasn't going to happen. People were going to know how bad this thing is, they were going to know what embarrassing hypocrites populate the Republican party, and they were going to know there was no supposed principle that Republicans won't abandon.