Noah Millman hopes that tonight’s primary will help put a stop to Rubio:

Laying my remaining cards on the table: I genuinely believe Rubio is the most dangerous candidate of the whole bunch, more dangerous than Trump and certainly more dangerous than the declaredly more-extreme Cruz. It’s partly that Rubio’s foreign policy views are exceptionally ideological and divorced from reality, but more that his whole political identity seems to me to have been engineered based on positioning, and positioning within the world of professional ideologists. The candidate he reminds me of most is John Edwards, and I loathed Edwards.

Millman thinks that too much has been made about the debate glitch, but I think it was an especially revealing moment because it happened when Rubio was put under real pressure for the first in the entire campaign. As McKay Coppins explains, it fits into a larger pattern of behavior that the public hasn’t been able to see:

But to those who have known him longest, Rubio’s flustered performance Saturday night fit perfectly with an all-too-familiar strain of his personality, one that his handlers and image-makers have labored for years to keep out of public view. Though generally seen as cool-headed and quick on his feet, Rubio is known to friends, allies, and advisers for a kind of incurable anxiousness — and an occasional propensity to panic in moments of crisis, both real and imagined [bold mine-DL].

The problem with Rubio’s response to Christie’s attacks wasn’t just that he fell back on rehearsed lines again and again in a weird way, but that he did so because he was clearly rattled and panicking. That might be dismissed as a fluke, but it confirmed several things that many observers already thought about him. It also showed how easily he can be shaken by an attack, and that fits with the pattern Coppins describes. Leaving aside all other flaws and bad policies, someone that has a “propensity to panic in moments of crisis” is not the sort of person most voters would want to have in the White House. The question hovering over Rubio all along has been, “Is he ready to be president?” That question was answered over the weekend, and the answer was no. That’s why I’m a bit puzzled why he thinks emphasizing his electability is the smart thing to do, since he just showed that he isn’t going to cope well with the pressures of a general election campaign.

That brings us to the comparison with Edwards. The comparison comes up now and then, and it makes more sense each time I see it made. As far as I know, Brian Beutler was the first to make the comparison, but it keeps coming up because the two do resemble one another in a few ways. Instead of Edwards’ “son of a mill worker” routine, we hear endlessly about Rubio’s father the bartender and his mother the maid, and both present themselves as smooth, polished operators that are going to expand the appeal of their respective parties by leaning heavily on their biography and family history. Originally, Edwards was trying to imitate Clinton by running as the “centrist” Southern Democrat in 2003-04 with the promise that he could make Democrats more competitive in the South and with working-class whites in general. The argument for Rubio has long been that mainly by virtue of being young, Cuban-American, and the son of immigrants that he would be able to win over voters that traditionally don’t support the GOP. Both the Edwards and Rubio arguments are exceedingly superficial, and so are the candidates that make them.