This appears to be the marquee moment from last night’s debate…

Mitt Romney isn’t good posting attacks in a debate. He doesn’t have enough personality to pull it off. When he tries outrage, it looks fake. And Romney has a real problem saying something memorable.

Newt, on the other hand, can fire off a memorable line as easily as blinking. So when Romney tries to take his hacks, Gingrich simply fires back that “he may have been a good financier; he’s a terrible historian.” And just like that, nobody even remembers what Romney was trying to say.

All along, Romney’s campaign strategy of standing by the riverside and waiting for the bodies of his opponents to float past has been maddening to watch, because it comes off as arrogant and dismissive of the electorate when he doesn’t make a concerted effort to actually earn the nomination.

But when you see him get schooled by Gingrich as badly as that clip demonstrates on an issue which is clearly a weakness for the former House Speaker, you begin to realize that maybe Romney just doesn’t have the chops to do much else beyond waiting around for his opponents to implode.

That’s not inspiring. What else isn’t inspiring is Romney’s camp instructing him to demonize Gingrich at the debates.

Look, people already know that Newt’s home life was a disaster and that he cheated on two wives. They already know that he’s done some things in and out of office which benefited his interests more than the country’s. That’s priced into his stock.

Gingrich is on the rise anyway because he’s aggressively presenting a bright-line differentiation between his vision for the country and Obama’s vision, and he’s denigrating Obama’s vision in no uncertain terms. He has heresies within his record which make conservatives uncomfortable with him, but in the absence of a compelling candidate with an unmistakable conservative record it’s the candidate who can best talk the talk who will move the needle.

The best attack on Gingrich isn’t to challenge that record. The best attack on Gingrich is to match his vision. Which Romney inexplicably can’t or won’t do.

The entire raison d’etre of Romney’s campaign is that he’s electable, more so than anybody in the GOP race. He looks like somebody out of Central Casting as a presidential candidate, and he has the kind of tone and presentation that, were he president, would probably instill a measure of confidence if not inspiration in the public.

But the way you make that perceived electability work for you isn’t by trashing Gingrich. Ultimately this isn’t about Gingrich, or at least it hasn’t been thus  far. It’s more about Romney.

Most Republican voters take William F. Buckley’s standard to heart – namely, they’ll vote for the most conservative candidate they think can win. Fine – Romney can win. But if he’s not conservative, what good does it do to vote for him?

Romney has to start talking the talk to conservatives. Beating on Newt’s record, with Newt on the stage to respond, won’t get him anywhere. And once Romney’s campaign is seen as flagging, he’s done. At that point it’s his body floating downriver.