Ted Cruz is also a Tea Party/Club for Growth–approved hero with sky-high conservative scores that should cheer those groups. (ACU: 100 for 2014, 100 lifetime; Heritage Action: 100 and 98; Club for Growth: 92 and 96.) Alas, Cruz’s go-it-alone style has limited his effectiveness as a lawmaker who can pass legislation. Cruz’s Senate website cites just one piece of legislation that he has guided into law: a 2014 statute that would bar entry visas to U.N. ambassadors who have committed espionage or terrorism against the United States or threaten U.S. national security.

Also telling: Among those who work closely with both of these men, three Republican senators have endorsed Rubio – Montana’s Steve Daines, Colorado’s Cory Gardner, and Idaho’s James Risch. In contrast, none of Cruz’s Senate colleagues recommends him for president.