Back at national headquarters in Houston, Roe and his team invested several million dollars in a data analytics operation. There were about 175,000 Republicans in Iowa who had participated in a presidential caucus, and Cruz’s statisticians and behavioral psychologists set out to learn everything they could about them.

The campaign conducted “psychological targeting” of likely caucus-goers, building its own version of a Myers-Briggs personality test to categorize Republicans so it could send them personally tailored phone calls, mail and other messages.

Sitting in his office last week, with war-strategy tomes by Sun Tzu and Carl von Clausewitz stacked on his desk, English looked out at the bustling phone bank, which on this afternoon included Rafael Cruz.

“If anybody goes to caucus and says, ‘I haven’t seen Ted Cruz,’ I want it to be their fault, not ours,” English said.

For the first six months of the campaign, he was the lone Cruz staffer in Iowa, and he worked out of the basement of his home. By August, though, there was a headquarters in Urbandale, then more staffers. The team grew to 20, and Cruz rented out a dormitory building in Des Moines — “Camp Cruz” — to house volunteers from Texas and other places who came in the final month to help canvass.