DES MOINES, Iowa — Mitt Romney admits his eight-vote Iowa caucus victory was “pretty narrow” but says he’s got more staying power than runners-up Rick Santorum and Ron Paul or his other rivals for the Republican presidential nomination.

Heading off to New Hampshire, where Romney holds a healthy lead in the polls, the former Massachusetts governor predicts a long road to the nomination. Romney says his national campaign team and strong fundraising will set him apart from the pack.

He told CBS’ “Early Show” on Wednesday that he will take his campaign all the way to the Republican convention in Tampa and predicts others are going to find that hard to do. One candidate — Rick Perry — is already stepping back to decide whether to stay in the race after a fifth-place finish.