THE SCORE is 2 to 0 so far in the Justice Deartment's prosecutions of the Abscam bribery cases. That result was hardly unexpected. The prosecutors were not likely to seek indictments in cases of this magnitude unless they rated the chances for convictions high.

But the fact that two trials have been successfully concluded (from the Justice Department's point of view) does not provide an answer to questions that were raised last winter about the tactics used by the FBI in the original investigaton. In both cases, the trial judges have yet to rule on claims that those tactics violated the civil rights of the defendants.

The lawyers for John W. Jenrette Jr., for example, kept pointing out during his trial that while meetings at which incriminating events occurred were carefully documented on video and audio tape, meetings at which he says exculpatory events occurred were not so documented. It will be months before the courts finally decide whether this claim and a similar one made by Michael Myers have enough substance to affect the outcome of the trials.

The fact that the trial judge in the Jenrette case has taken this issue quite seriously makes it important to reserve judgment on the entire Abscam operation at least until the other four defendants are tried. Perhaps more material will come to light during their trials to answer the still troubling questions of how the FBI came to focus on these particular members of Congress and what kind of enticements it provided.

The existence of these unanswered questions and the legal issues they raise underline the importance of the way in which the House handled the motion to expel Mr. Myers. The decision to throw him out was based not on the verdict the jury had returned in court but rather on the findings made by the House ethics committee after it conducted its own investigation.

That is as it should be. There may be situations in which the conduct of a member is so grossly unethical that expulsion is proper whether or not he can be convicted of a crime. That was true, in our view, in the Myers case; the acts he admitted to, while sufficient -- if true -- vitiate his conviction, were also more than sufficient to justify his expulsion.

The same procedure should be followed by the House in dealing with Mr. Jenrette and the other four members who are under indictment. Their cases may not be as clear-cut as that of Mr. Myers was, but the fact that they may be difficult doesn't mean judgment should be postponed. The ethics commitee needs to examine each of them with care not only to guarantee each member a fair hearing, but also to put itself in position to express an opinion -- once all the trials have been concluded -- on the propriety of the way the Abscam investigation began and was conducted.