Yet his initial venture into presidential politics is by turns a confirmation of and a complication for the professed Cruz image.

The race installed Mr. Cruz as a creature of the Republican establishment — but also helped start his divorce from it. He made plenty of enemies among party operatives, according to interviews with over a dozen former colleagues, though for reasons that had little to do with ideology.

“I was far too cocky for my own good,” Mr. Cruz wrote in his book, “A Time for Truth,” explaining how the burned bridges probably cost him a desired job in Mr. Bush’s White House, “and that sometimes caused me to overstep the bounds of my appointed role.”

On this point, Mr. Cruz and his detractors agree.

By the end of five bleary-eyed weeks of hanging chads and butterfly ballots, Mr. Cruz had aggressively worked his legal connections, chafed when he felt sidelined by party veterans and — even in the view of some who disparage him — helped ensure Mr. Bush’s victory in the courts, to a point.

In fact, former colleagues say, the Ted Cruz of 2000 is entirely recognizable in the candidate now aspiring to the presidency himself, fusing hyper-intelligence, crackling ambition and a laundry list of impeccable insider credentials that he once ticked off more readily.