IT’S EASY TO jump to conclusions about a case like the one against S.C. Agriculture Commissioner Charles Sharpe — a case that’s either lurid or ludicrous, depending on your perspective. But the fact is that neither the case against Mr. Sharpe nor what we’ve seen to date of his defense is as straightforward as it seems.

Both sides have to do more than just make what sounds like a logical case if they hope to prevail.

The case against Mr. Sharpe sounds like a slam-dunk:

Police have tape-recordings of the former House member trying to convince them not to bring charges against the people who ran an illegal cockfighting operation in Aiken County, by arguing that they were merely “testing” roosters’ physical prowess by forcing them to fight to the death. Indictments say Mr. Sharpe assured the police who were secretly taping him that this testing was legal, and he claimed that an attorney general’s opinion backed him up. (That was a lie.)

Further, Mr. Sharpe admitted taking money from the cockfighting promoters, which he reported as campaign contributions; and prosecutors say they have bank records that show he took additional payments for himself, and then tried to disguise their source.

But even if every bit of that is true, Mr. Sharpe could still walk free, if prosecutors can’t tie the attempts to help the cockfighters directly to the money.

It’s not against the law to try to convince people that an illegal activity is legal. If it were, then some of the most prominent members of the General Assembly would be in prison today, for all the verbal gymnastics they went through trying to convince their colleagues, the public in general and, at least indirectly, police that the video gambling industry wasn’t breaking the law when it was promising and delivering huge jackpots.

It’s not against the law to accept campaign donations from people who are engaged in illegal activities — even if you take the money at the same time you’re trying to convince others that their criminal actions are within the law. If it were, again, many legislators would be in prison today. The biggest advocates of the video gambling industry in South Carolina received tens of thousands of dollars in donations from the poker barons.

In order for prosecutors to win a conviction, they have to prove a direct quid pro quo; that is, that the money was demanded or given in exchange for the action, or the promise of action. (The standard is a bit lower when the money isn’t a campaign contribution: Prosecutors need prove only that there was an expectation of a quid pro quo. But still, the linkage is essential.)

The cynics among us will respond to such requirements with a loud “Duh,” but this is no mere technicality. Just ask the federal prosecutors who handled Operation Lost Trust a decade and a half ago: Four trials into the corruption probe, the U.S. Supreme Court added the quid pro quo requirement, declaring that it was no longer sufficient to prove merely that an elected official used his position to help a donor. And prosecutors’ one loss at trial came when the defendant convinced the jury that his vote for pari-mutuel betting was not tied directly to the campaign donation he accepted from the undercover lobbyist who was pushing the gambling legislation.

But if prosecutors have several hoops they must jump through to convict Mr. Sharpe, the agriculture commissioner has even more if he hopes to avoid conviction.

Mr. Sharpe, through his attorney, responds to the charges by saying that he believed the cockfighting operation was legal. If that’s true, then he’s not very bright. But, frankly, it doesn’t matter what Mr. Sharpe believed. Even if he can convince everybody in the state that he really did believe he was supporting a legal operation, prosecutors can still convict him if they prove his actions were tied to the cash.

To prevail, Mr. Sharpe must frustrate the government’s efforts to show that there was a connection between the money he accepted and the favors he did for the cockfighting racket. For all practical matters, that means he’ll have to convince a jury that he would have acted as he did even if he wasn’t getting any money, and that the cockfighters would have given him money even if they didn’t expect anything in return.

In fact, it wouldn’t even matter if the cockfighting operation were legal. We usually associate bribery with attempts to protect people from prosecution for their crimes (as is alleged in this case) or to make the illegal activity legal (as in Operation Lost Trust). But the legality of the activity is irrelevant. An elected official who took money in exchange for opposing a tax increase or for supporting better funding for schools would be just as guilty of extortion as one who was paid off by the mob.

This, of course, is where the cynics will again chime in: That’s what all campaign contributions are. And there’s no question that, at least in the case of some donations and some elected officials, the line between legal campaign contribution and illegal bribe is nearly too thin to measure — and often measured in the sophistication of the nod and the wink of the participants, rather than in reality.

In this case, the sleazy nature of the allegations, and the “I’m stupid” defense might well blur the line. But I suspect that in the end, it will be quite thick, and quite bold.

Ms. Scoppe can be reached at cscoppe@thestate.com or at (803) 771-8571