Jeb¯\_(ツ)_/¯
By 
Rubio dispatched Bush with a tone so understated, and almost pitying, it marked the instant and widely acknowledged death of Bush’s hopes. Rubio now inherits from the vanquished Bush the role of champion of Bushonomics and the general Bush strategy of combining folksy personal appeals, tiny dollops of policy for the working class, liberal instincts on immigration, and a fanatical devotion to the policy agenda of the party’s donor class. Rubio is more like George W. Bush than Jeb Bush ever was. By the time the campaign is over, not only will all of Jeb’s donors have defected to Rubio, Poppy Bush may be signing over Jeb’s share of the family inheritance to Rubio.
And that was it. Bush was finished. He spoke again throughout the night, but never with energy. Any wind he had—any fire or spirit—was gone. In a few seconds, Rubio had knocked Bush out of the game completely.
Put differently, if this was an “establishment” debate—hosted by CNBC, focused on the economy, and meant to give voice to the most viable candidates in the race—then it served its purpose. Bush might have cash reserves and support from family backers, but after tonight, he’s slipped to the second tier. He may not leave the race, but he’ll struggle to get traction. Now, Rubio—who gave another great performance—takes his place as the most viable candidate in the race, and as the closest thing to a front-runner.
Bush received poor reviews for his debate performance from political commentators of all stripes (Republican, Democratic, partisan, nonpartisan, reporters, “data journalists”), many of whom also suggested that his campaign might soon be over. The straw poll1 we conducted among FiveThirtyEight writers and editors agreed; Bush’s average grade was a C-, putting him at the bottom of the 10-candidate group.
And it’s not just from people inclined to mock him ex ante! From someone who was comparing Jeb¯\_(ツ)_/¯ to Obama earlier this year, we get this:
He arrived at both the second and third debates with plans of attack against his chief rivals of the moment: Donald Trump last time, Marco Rubio this time. Both times, he failed to anticipate and prepare for the most obvious opponent reaction. What followed were humiliating climb-downs by Bush.
“Apologize to my wife!”
“No.”
“OK.”
“Resign from the Senate!”
“No.”
“OK.”
[…]
He comes with one punch, whiffs it, and then the energy seeps out of him for the rest of the evening. Watching Bush soldier through the hour and 40 minutes after his sad bungle with Rubio was like watching an army marching on a slow dejected retreat. He was listless, depressed, and perfunctory. His post-debate interview was downright defeatist.
As several of the quoted people also observe, it’s hard to separate cause and effect from Jeb¯\_(ツ)_/¯’s trainwreck. He was already in deep, deep trouble before the debate — when your only asset is access to establishment money, you can’t survive them parking there money elsewhere for long. But the debate both illustrates why he can’t get any traction and further contributed to his decline. I’m not sure if he even makes it to Iowa at this point.
And I feel even more strongly that things are breaking beautifully for Rubio. Cruz, the other serious candidate standing, will have more natural appeal to the base, but as long as Trump and Carson stay around they figure to hurt Cruz much more than Rubio. The party will close ranks on the latter, and Cruz will have to do very well in the first states to overcome that.