An article in yesterday's Washington Post said that former senator Daniel B. Brewster (D-Md.) was convicted of bribery. That charge -- the one for which he had been indicted -- involves "corruptly" accepting money for being influenced in performance of official acts. Actually, Brewster was convicted of three counts of accepting an "unlawful gratuity," a lesser form of bribery. It involves "willfully and knowingly" receiving money personally for an official act, without corrupt intent. The U.S. Court of Appeals here, ruling that the jury instructions were faulty, overturned the conviction and ordered a new trail. Brewster, without admitting guilt, pleaded no-contest and was sentenced. He had gone to trail after the Supreme Court, in its only ruling in the case, held that the constitutional protection of congressional speech did not bar prosecution.

What's the difference between the legislator who takes a bribe from X to introduce a bill, and the legislator who takes a campaign contribution from X and then introduces the very same bill?

That question has arisen in the past when a Senate or House member has been prosecuted for bribery.

It is arising again because the FBI has reportedly videotaped several members of Congress taking money from undercover agents posing as Arab sheiks or their representatives.

It is part of the U.S. political system for members of Congress to take money or things of value legally.

Mostly this is in the form of campaign contributions or honorariums. Often the money is given in the hope that the receiving member of Congress will someday vote the giver's way.

How is an illegal bribe any different?

For a prosecutor, the essential question is whether he can prove -- beyond a reasonable doubt -- that a suspect acted corruptly. He has to show intent, and that is often hard to do (though it could be less so in this case, because of the videotapes).

The part of the federal criminal code that fits most snugly around the known circumstances of the "sting" operation is section 201 (c) (1).

The pertinent languaage says that a member of Congress commits an offense if he, "directly or indirectly, corruptly asks, demands, exacts, solicits, seeks, accepts, receives, or agreees to receive anything of value for himself or any other person or entity, in return for . . . being influenced in his performance of any official act."

Perhaps the severest test of the government's ability to distinguish between a bribe and a legal campaign contribution was posed by the case of former senator Daniel B. Brewster (D-Md.).

He had accepted campaign contributions from Spiegel Inc., a mail-order firm based in Chicago, and he had, as a member of the Senate Post Office and Civil Service Committee, taken a position on pending postal legislation that coincided with Spiegel's.

Brewster was convicted of bribery. At his sentencing in 1973, asking what he had done wrong, he said he had a list of others in the House and Senate who also had accepted campaign contributions from Sepigel. "If I am guilty of anything," he argued, "so are all these other men."

In addition, Brewster said, he didn't need to be bribed to take the position he'd taken on the postal legislation, because that was the position he'd always taken.

The trial judge instructed the jury that it is entirely legal for a campaign contributor to give money in the hope that the recipients will continue to hold positions generally compatible with their own.

But the jury, finding that more than hope was at issue, held that Brewster had acted corruptly by giving his quid for Spiegel's quo.

The conviction was upheld by a divided Supreme Court. The majority emphasized that the government may prosecute a member of Congress provided that its case "does not rely on legislative acts or the motivation for legislative acts." In the "sting" operation, so far as is known, no legislative acts occurred.

A prosecutor, in addition to having to show corrupt intent, may have to deal with the defense of entrapment.

It is a defense that objects to the methods that were used to gather evidence of guilt -- but it doesn't deny built. For that reason, entrapment is a particularly unattractive defense for defendants who were elected to positions of public trust.

That aside, the courts have defined entrapment pretty much the way prosecutors want it defined. The key question isn't whether law-enforcement officer used this or that stratagem or enticement but whether the accused showed himself disposed to commit an offense.

In any event, criminal prosecutions may not be the only arrow in the government's quiver. Ther's also the possibility of a suit to recover bribe money from its once-trusted servants. Such a suit is appealing in part because it's a civil action: there's no need to prove an intent to act corruptly or to prove guilt beyond a reasonable doubt.

A precedent for a damage suit was created in 1973 by the U.S. Court of Appeals here when it upheld a government suit accusing Henry Kearns, former president of the Export-Import Bank of the United States, of a breach of fiduciary duty.

In 1969, the government sought to recoup the fees that Robert G. (Bobby) Baker allegedly collected for selling his influence while secretary to the Democratic majority of the Senate. The suit ended with an out-of-court settlement.