In last night's debate, the worst moment in an interlude of awfulness for Texas Gov. Rick Perry was an act of charity from Mitt Romney, who certainly has no apparent affection for Perry. As his rival tried to recall the third agency he’d eliminate, Romney suggested helpfully, “EPA?”

Perry repeated it, as if it were the right answer. Then moderator John Harwood asked if that was the third agency he had in mind. No, Perry said sadly, he couldn’t remember the third.

The Romney camp decided to forgo the mass e-mails during the debate that are intended to bolster a candidate’s positions. It wasn’t needed. Romney said nearly everything he needed to onstage. Perry’s team was sending the missives out in record speed, prompting some on Twitter to query whether the e-mail author wouldn’t be a better candidate. The Romney team was mum about the “moment’; they know enough not to taunt in the end zone.

Perry is touring the morning shows today and trying to diffuse the matter with humor. But of course the thought that such an episode could occur in a general-election debate against President Obama strikes fear in the hearts of Republicans. Perry might succeed in recapturing some likability, but his viability as a candidate is gone.

The moment was made worse by the nature of the memory lapse. He wasn’t straining for a name or date. He couldn’t recall his own plan. That plan is supposed to be the centerpiece of his comeback, and yet it is as foreign to him as humility is to Newt Gingrich.

The good news for him is that he wasn’t the only one who obviously didn’t know his material. Herman Cain now uses his 9-9-9 broken record as a substitute for familiarity with most any other subject. I can hardly wait for the foreign policy debates. Instead of 9-9-9, his all-purpose answer will be “Consult my advisers.” But given that Mark Block is his most prominent one, that’s small comfort for many voters.

Fittingly, Sen. Jim DeMint (R-S.C.), once thought to be a conservative kingmaker, let it be know both Perry and Cain were blowing it. “It is a problem,” he told Politico. “We need to stay on message, and the last week has not been good to focus on jobs and economic growth.” Translation: You’re handing Romney the nomination on a silver platter.

The silver lining to all of this is that it is increasingly hard to fake your way through a rigorous presidential primary season. Cain’s past and his current lack of knowledge have caught up with him. Perry’s lack of rhetorical skills and policy chops have done him in. All that “fly-speaking,” as Cain calls it, has its benefits.