Some legal experts may call it "prosecutorial discretion," but U.S. Attorney Joseph E. diGenova seems to have abandoned any semblance of consistent standards for the treatment of lawbreaking demonstrators in this world capital of protests. If you demonstrate at the South African Embassy against apartheid, you get arrested but the charges are dropped; yet if you demonstrate at the Supreme Court building against abortions, you are likely to go to court and be sentenced to one day in jail and a fine of $10 (with credit for the day you spend in jail after arrest). What's the difference? You try to figure it out:

In announcing that he would press charges against abortion protesters, Mr. diGenova offered no explanation for his reasoning. Before this, Mr. diGenova had said he would not prosecute the anti- apartheid demonstrators, noting that the arrests at the South African Embassy lacked "prosecutive merit." As it happens, neither group is happy with its treatment. The embassy protesters wanted their day in court, with all the attendant public exposure and possible punishment. The anti-abortion protesters, on the other hand, claimed that to prosecute them is to persecute them. This "is not equal justice under the law," said National Right to Life President Jack Willke. John Cavanaugh- O'Keefe of Human Life International argued that the issues raised in the two cases are identical: "Either they're going to enforce the law or they're not. It's straightforward discrimination."

At least Mr. diGenova didn't cite the merits of the demonstrators' views as grounds for deciding whether to prosecute, as the D.C. Corporation Counsel did in some embassy cases in which it had jurisdiction. That, as local attorney Matthew Watson noted on the op-ed page last month, "is unacceptable in a free society." Still, the public is left with the impression that one group of protesters is prosecuted and sentenced while another gets off entirely.

Does this mean protesters should check in with the prosecutor before demonstrating, to see if it's a "charge" or a "drop" situation? Of course not. Prosecutors may have almost unlimited latitude in deciding which cases they want to take to court, but there's certainly no law against their explaining to a baffled public what it is they think they're doing for the cause of justice.