Before the Summer of Trump, Jeb Bush seemed to be the inevitable GOP nominee. Well, if not inevitable, then at least most plausible on paper. The one thing he had to overcome was his last name, by which I mean the legacy of his brother’s failed presidency. If he could do that, it would likely be smooth sailing for him.

It hasn’t happened. His George W. Bush’s legacy hasn’t even been much of an issue to this point, but Jeb’s campaign is dead in the water, and sinking fast. This brutal assessment by Chris Cillizza, written after last night’s debate, nails it. Excerpt:

He just isn’t all that good at this. And he knows it.

There’s no other conclusion that you could draw after watching Jeb Bush flail in Wednesday night’s Republican presidential debate. Bush looked overmatched and lost — an image made all the worse by the fact that he was positioned on the stage in Boulder, Colo., next to Marco Rubio, his one-time political mentee but now quite clearly his superior in the race.

Bush’s attempt to attack Rubio was a metaphor not only for his debate performance but for his campaign. Knowing he needed to land a clean punch on Rubio, Bush piggybacked off a question from the moderators about Rubio’s sparse attendance record in the Senate and tried to attack. But Bush doesn’t really like attacking. And he backed into it from the start. “Could I bring something up here?” he asked, before somewhat awkwardly and, if I’m being honest, nervously, said this of Rubio: “I expected that he would do constituent service. Which means that he shows up to work.”  Then Bush, in an obviously prepared line, joked that Rubio was following a “French work week.” (Ugh. Sad trombone.)

Rubio, ready for the hit, calmly dispatched a series of facts — including that John McCain missed lots and lots of votes in 2008 and Bush still backed him — before delivering this howitzer: “The only reason you are doing it now is because we are running for the same position, and someone has convinced you that attacking me is going to help you.”

The crowd cheered. Bush folded his hands and tried to respond. It didn’t work. It was over — in more ways than one.

Read the whole thing. If you didn’t see Jeb’s feeble attempt to smack Rubio, and Rubio’s taking him to school, it’s here:

If I were a Bush donor, I would either close my checkbook or redirect my tithe to Rubio. Jeb said the other day:

If this election is about how we’re going to fight to get nothing done, then I don’t want to have any part of it. I don’t want to be elected president to just sit around and see gridlock become so dominant that people are literally in decline in their lives. That is not my motivation. I got a lot of really cool things I could do other than sit around and be miserable, listening to people demonize me and feeling compelled to demonize me.

Hey, I agree! I don’t blame him one bit for feeling that way. It’s a perfectly sane way to feel, and I think it speaks well of Bush’s humanity that he thinks this way. But it speaks very poorly of his prospects to be president. Given his somnolent debate performances so far, it’s all too easy to see Hillary Clinton eating him alive in the campaign.

I don’t know, though, if Bush, having raised so much money (a total of $133 million, far ahead of his GOP rivals) has a graceful exit. I suspect his donors will, in effect, make the call for him after last night’s debate, by finding some better investment to make.