As establishment Republicans continue to clamor for a Chris Christie presidential candidacy, some GOPers have started to speak up about what a Christie run would look like in reality. Their message: Time’s running out for Christie and any other non-candidate candidate.

On CBS’ “Face the Nation” this morning, for example, Sen. John McCain warned “the swimming pool looks a lot better until you jump right in. The water may not be quite as warm as you think.”

He had positive words to say about Christie himself (“he’s a good governor”), but still maintained he’d be “starting from way behind in fund-raising and organization and other areas.”

No doubt that’s true: Third-quarter fundraising closed yesterday and advance reports of candidates’ campaign cash show they’d have an undeniable head-start on any candidate who so far hasn’t been assiduously courting donors. But, then again, if the donors are courting the candidate … perhaps that wouldn’t be much of a factor.

Meanwhile, on NBC’s “Meet the Press,” Virginia Gov. Bob McDonnell (who has said he’d be open to the VP slot) echoed McCain.

“[Christie] said for a year he’s not,” McDonnell said. “I just think whoever’s going to get in needs to do it immediately.”

McDonnell, too, is right on the money: Presumably, conservatives want Christie’s “no” to mean “no.” Wouldn’t that be a refreshing reminder of what real conviction, honesty and sincerity look like?

And finally, on this weekend’s broadcast of “Fox News Sunday,” Fox News commentator Brit Hume also reiterated the two GOP politicians’ warning of the short runway ahead of anyone who decides to enter the race now.

“You have to get, from almost a standing start, up to speed on national and international issues in a big hurry because there is a debate coming about every week,” Hume said. “There are going to be six more before everybody votes and you have to stand up on the stage and shine, because you’ll sort of be expected to. Expectations for this poor guy are over the moon. You’re going to have to stand up there against all these people who have been doing this for a while and have gotten better at it. So, I think, if he gets in, he better do it fast.”

But Hume also took issue with the Christie-coercers themselves.

“With all due respect to my esteemed colleague Bill [Kristol], people who are chasing after Gov. Christie remind me of a pack of dogs chasing a car, and it’s not clear what they will do if they catch it,” Hume said.

Good for Hume. That’s a much-needed reminder from him to ask ourselves just what our end in mind really is. To win? Or to field a particular kind of candidate? A little of both? Personally, this is when I think we should start advocating a Heritage Foundation-style Mandate for Leadership. Let’s stop thinking so much about who we want and start thinking more specifically about what we want our candidate to do once he or she is in office — and start seeking buy-in for those policy proposals now. We’ve gotten all the candidates to promise Obamacare repeal: What other policies might we compel them all to support if we make our will clear enough? Just consider: Reagan passed out Mandate to his Cabinet members at their first meeting — and, at the end of his presidency, nearly two-thirds of the policy recommendations contained therein had been enacted. Pretty impressive, huh?

Here’s the Hume clip: