“If they’re looking for an entertainer in chief, I’m probably not the guy,” former frontrunner Jeb Bush confessed to CNN, minutes after the third Republican debate. After three poor debate performances, Bush understandably wishes to minimize the importance of these encounters. And he has a point. It’s hard to imagine Dwight Eisenhower doing well under the artificial and often absurd conventions of televised debate. What’s lethal for Jeb Bush’s presidential ambitions, however, is not the mere fact that he underwhelms on the debate stage, but the particular reasons he underwhelms—these five perhaps above all.

Jeb Bush is chronically unstrategic.

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.”

Jeb Bush does not improvise.

His confrontation with Marco Rubio did not have to end badly for him. When Marco Rubio brushed off criticism of Rubio’s absenteeism from the Senate by invoking John McCain, Bush could have hit back hard. “Seriously Marco? You’re comparing yourself to John McCain? McCain is an American hero, he’s chairman of the Senate Armed Services Committee, he created the 9/11 commission, he’s written more laws than you’ve read. The problem is not just that you’re away a lot ... the problem is that you don’t do anything even when you’re there. Frankly, you’ve never done anything.” Then—sticking the knife in—“Why Marco, you even failed to pass the immigration amnesty deal you co-wrote with Chuck Schumer.”

Bush does not improvise because he dreads confrontation.

If somebody writes an attack line for him, he can deliver it—unenthusiastically, emphasis in the wrong places, undramatically—but still: It’s delivered. But that’s it. When it fails, as it always does, he cannot, on his own two feet, find an effective way forward or a dignified way back.

When Bush fails, he discourages easily.

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.

When discouraged, Bush—although a physically big man—psychically shrinks into his own feelings of hurt and rejection.

Twice, Bush has said that if the campaign is going to be a ridiculous carnival, he doesn’t want to participate. Guess what? Presidential campaigns are always, to a considerable extent, ridiculous carnivals. But that’s not the only thing they are, or have to be, and it’s the quality and character of a presidential candidate to elevate them into something more.

But even more worryingly: Notice how often Jeb Bush—when he meets adversity—reverts to talking about himself and his feelings. Many politicians suffer moments of depression, but the good ones can take a punch and keep smiling until the opportunity arrives to hit back. All politicians are self-involved, but most at least can remember to put the public first when the microphones are switched on. Not Jeb Bush. As Philip Marlowe says to Terry Lennox in Chandler’s The Long Goodbye: “You talk too damn much, and it’s too damn much about you.”

More and more, it seems no coincidence that he succeeded in government so long, and only so long, as a real estate bubble lifted his state’s economy. He was a man for one season, the languid summer, and not our present time of storm and ice.