CNN’s John King is in an unusual position on Thursday night. He will moderate the last and maybe most decisive debate before the South Carolina primary. There is a lot at stake, including rehabilitating his own reputation.

You may recall back in June when he moderated the Republican debate in New Hampshire. At the time I wrote:

[M]oderator John King distinguished himself as the worst moderator in the history of televised debates. He interrupted and cut off the candidates, making both himself and time limits an unwelcomed intrusion. He very annoyingly pestered the candidates with “this or that” — Elvis or Johnny Cash, Connan or Leno, etc. Had he not used up precious time during the substantive part of the debate, this might have been excusable. (His curious grunting will be fodder for Saturday Night Live spoofing.)

What was not excusable was conducting a debate for one hour and forty minutes before asking a single foreign policy question.

So the challenge for King on Thursday is to show, at a minimum, that he is a serious news person

Moreover, unless he wants to follow in George Stephanopoulos’s footsteps he’d be wise to stick to issues that Republican voters care about and leave the contraception, evolution, and other make-them-look-like-yokels questions to others.

It would also do King well to provide at least a semblance of fairness. In a rather jaw-dropping account, the New York Times explains how the Fox News team crafted a “get Romney” debate:

It is one of the quirks of the 2012 campaign: the number of debates seems not to have diminished their significance or the expectation that they should create a media moment. In fact, as the Republican field shrinks, Mr. Baier and Fox view themselves as one of the last lines of defense to fully litigate Mr. Romney’s record before millions of viewers. . . .

There are candidates who still believe that there is a conservative base out there that is not going along with what they’d call Governor Romney’s coronation,” he added. “And they’re determined to continue the fight. Now, whether they can make the stand in South Carolina or not is really a story line that I think this debate directly affects.

Rather presumptuous, isn’t it, to designate Romney as the only one for whom a special vetting process need be designed. (“At one point during the prep session, Gerald F. Seib, the Washington bureau chief for The Wall Street Journal, asked in earnest, ‘Does anyone have the feeling like we’re ganging up on Romney?’” If you have to ask. . . .)

So what could King do to help himself and avoid appearing to be invested in the outcome? It would seem the task is two-fold. First, there is a genuine debate between Romney and Newt Gingrich on capitalism. Is there such a thing as good and bad capitalism? How do they intend to defend conservative economic principles against President Obama’s plea for “fairness”? Second, Gingrich seems to think he’s the only viable contender to Romney, yet he’s never been elected to more than a congressional seat, has many of the infirmities that conservatives see in Romney (e.g. support for the individual mandate) and a load of personal baggage. Why does he think he is superior to Rick Santorum as the not-Romney candidate? And conversely, Santorum should be allowed to state his case as to why he is more consistent, conservative and electable than Gingrich.

King’s goal on Thursday should be to let the candidates go back and forth, and not to inject himself (as he did in the last debate). If he can do that and not bring up contraception, he’ll go some way in restoring his own moderator credentials.