By Byron York

NEA Columnist

The conventional wisdom that Jeb Bush is dead has become so unanimous it's only natural to suspect it's wrong.

Yes, the polls are atrocious. Bush, now seeking traction with a New Hampshire tour, is at 4 percent in a recent Fox News national survey and a weak fifth in the RealClearPolitics average of polls. The trend, for the moment, seems to be down, down, down.

Yet there is a not-crazy scenario in which Bush could rise again, not to dominate the race but to be in the running when the four candidates ahead of him self-destruct, kill each other, or run out of gas.

JebWorld held a focus group in New Hampshire the day after Bush's disastrous performance at the Republican debate in Boulder on Oct. 28. According to a source deep inside JebWorld, the result was not only not terrible, it pointed to five areas of promise for Bush:

1) A large majority of group members were undecided and felt no rush to decide anything. It's not even time to narrow their list of favorite candidates.

2) After all that has happened, the New Hampshire voters still had a positive, or mostly positive, impression of Bush. They see him as smart, mature and dull.

3) They like Donald Trump, think he's fun, but are concerned about giving Trump the vast powers of the presidency.

4) They love Ben Carson as a non-politician with a gentle bedside manner, but are a little discomfited by his offbeat views on a number of topics.

5) They see Marco Rubio as a perfect vice president and wonder if he is too young, and has too few accomplishments, for the top job.

JebWorld came away feeling that if Bush does better in the next debate -- not home-run better, but better better -- he can stop the slide. But stopping a devastating decline does not equal winning. There's no avoiding the fact that at this point in the game, the Jeb success scenario depends on other candidates falling.

Four of them, specifically. First, Trump. JebWorld continues to believe the New York billionaire doesn't have what it takes for a long, grueling campaign. But if Trump does last, the still-rich Bush super political action committee Right to Rise will have the ability to unleash millions of dollars worth of negative ads to exploit the doubts voters already have about him.

Next Carson. JebWorld believes Republicans are drawn to him because of his natural likeability and because he stands so far outside the political system. But they believe Carson's support is particularly soft, with 80-plus percent of Carson supporters saying they might eventually vote for someone else. That, plus Carson's own weaknesses and the heightened scrutiny he will inevitably receive atop the polls, will eventually bring him down.

That leaves Rubio and Ted Cruz, who could emerge as the two leaders after a Trump-Carson fadeout. One good-for-Jeb scenario would be that Rubio and Cruz then engage in an internecine battle so vicious, bitter and bloody that Republican voters come to believe neither is suited for the presidency.

In that case, Republicans look around and see Carly Fiorina, Chris Christie, Mike Huckabee, John Kasich, Rand Paul, Rick Santorum, Bobby Jindal, and Lindsey Graham, and ask: Now why was it we didn't like Jeb?

The other good-for-Jeb scenario, JebWorld believes, is that Cruz slays Rubio. Despite Rubio's solid progress in recent weeks, JebWorld believes he is all talk and is just beginning to face media scrutiny. Cruz -- sharp, aggressive, a formidable debater -- is coming up fast.

Even after that ruinous moment in Boulder, Bush is still taking shots at Rubio, but JebWorld would clearly be happy to have Cruz take up the fight. In the careful-what-you-wish-for category, JebWorld believes Bush would do well in a one-on-one against Cruz, and the Bush super PAC will still be there to carpet-bomb the last opponent standing.

All this could well turn out to be a total fantasy. The nicer way to put it is that Bush needs a lot of planets to align. And he could really use a break. That leads to JebWorld's last point: It's been said over and over, but Bush really believes longevity will be the key to victory -- who can stay in the race through the inevitable shakeups of December, January, and February?

The bottom line: Conventional wisdom says it's already over -- just Google "Jeb Bush" and "death watch" -- but conventional wisdom can always change.

Byron York is chief political correspondent for The Washington Examiner.