The next day, his aides set about the routine Capitol Hill tasks of scheduling speaking time for their boss on the Senate floor and printing out poster-board photos of the crisis in Venezuela, while Rubio jotted down a few notes on his flight from Miami to Washington National Airport. The expectation on Rubio’s staff was that he would give a straightforward foreign policy speech on an issue that mattered deeply to a distinct swath of his constituents — and that the rest of the country was prone to ignore.

But when Rubio arrived at his office around 4:30 p.m., he looked at the TV and saw Iowa Democratic Sen. Tom Harkin standing behind a podium, reciting a cheery travelogue of his recent trip to Cuba, where he toured a local block party and marveled at the country’s health care system. It was the sort of box-checking speech a politician gives when he wants to justify his “fact-finding” trip to a tropical island in January, and it was unlikely that anyone outside a small handful of C-SPAN obsessives would notice it. Rubio saw a slow-moving target.