The downside of Haley's endorsement for Rubio: Higher expectations to do well in South Carolina

Rubio’s team insists they are focused on winning a long-term delegate fight against Trump and Cruz. Yet both of those candidates have already notched wins. Sooner or later, to sustain the perception of viability, Rubio will need to win somewhere. And it’s not unreasonable to ask, as Miller did: If Rubio can’t win here, with most of the state’s Republican apparatus supporting him, where can he?

The danger for Rubio isn’t that he flops without a first-place showing here. South Carolina, at this early stage and with six candidates still alive, isn’t a must-win for anyone. But with Haley now on board, and the wind clearly at his back, Rubio would be devastated by finishing behind Cruz. That’s the scenario Cruz’s campaign — which is deceptively strong on the ground here — is teeing up as the media seizes on the narrative of Rubio’s rise. (Polls showed the two senators battling for second place behind Trump prior to Haley’s endorsement.)

To be clear: Rubio’s expectations are rightfully high here not just because he has these three influential state Republicans in his corner, but because his campaign has deep roots in South Carolina and always viewed it as Rubio’s best chance to score an early-state victory.