--- Senators generally refrain from impugning their colleagues on the floor, a practice codified in Senate Rule XIX: “No Senator in debate shall, directly or indirectly, by any form of words impute to another Senator or to other Senators any conduct or motive unworthy or unbecoming a Senator.” The penalty for breaching that rule is to be ordered to take one’s seat — in effect, to sit down and shut up. But no senator rose to make a point of order before Cruz left the floor. “It’s unusual, certainly,” Betty K. Koed, the Senate’s official historian, said of Cruz’s remarks....