I n early 2019 , Marco Rubio pressed his way through a dense crowd near Colombia’s border with Venezuela, his aides holding back refugees clamoring for a handshake or a photo with the man heralding the imminent arrival, they all felt sure, of liberty for Venezuelans. With his polo shirt dotted with sweat and a Venezuela Libre cap shielding his face from the tropical sun, the then-senator made an urgent appeal to the country’s security forces: Do the right thing and defy Nicolás Maduro’s