This (noted in the briefing) seems a good read of the state of the race at this moment:

Thus Rudy announced that he understands this truth: The GOP primary for president is either a one-man or a two-man race. Giuliani is a clear national front-runner, barring an unlikely meltdown on the part of the battle-tested former mayor.
And of all the other candidates in the GOP race, only one man is now in a position to threaten his victory — Mitt Romney.