I go through upside and downside scenarios for Cruz, Trump, and Rubio on the home page. Here is what I think the scenarios are for Cruz:
Ted Cruz Upside Scenario: A Commanding Position by February 20Cruz wins Iowa going away. This isn’t hard to imagine; in fact, I’d guess today that he wins by 8–10 points there. With some momentum into New Hampshire, Cruz finishes second there, behind Trump. For good measure, Rubio is beaten by, say, Chris Christie, and finishes fourth. The “establishment lane” fails to produce a strong, viable contender and Cruz goes mano a mano with Trump in South Carolina and gets enough mainstream Republican support to beat him and establish a dominant position for the nomination.
Ted Cruz Downside Scenario: Trumped!
In what would play as an upset, Trump beats Cruz in Iowa. Cruz has no momentum in New Hampshire and finishes fourth or fifth there. He goes into South Carolina trying to stop Trump, who has probably gone two for two in Iowa and New Hampshire. Even worse would be if Rubio finished strongly in both Iowa and New Hampshire and is competing with Cruz for very-conservative and somewhat-conservative voters. Cruz loses South Carolina and begins to look like a Trump spoiler going into the rest of the South.