Independent counsel Kenneth Starr has forced the issue. His subpoena of President Clinton to testify before the grand jury investigating the Monica Lewinsky matter might precipitate a constitutional crisis. Or, more likely, it could help wrap up a controversy that has entwined - and often irked - the American public for seven months.
The latter outcome is made all the more likely by Mr. Starr's apparent success in persuading Ms. Lewinsky, herself, to testify.
That increases pressures on the president, who faces vexing alternatives. He could refuse to comply with the subpoena, but that would inevitably raise parallels to President Nixon's refusal in 1973, which led to a Supreme Court order to hand over the Watergate tapes.
A demand for personal testimony is different, but it still involves information held by a president that bears on a criminal investigation. Mr. Clinton is said to be determined to avoid the "indignity" of appearing in person before the grand jury. Most Americans continue to rate his performance in office favorably, and they may be on his side here. But an outright refusal to testify could turn public opinion.
And should the president be able to avoid a duty that's mandatory for any other citizen?
Clinton's aides are negotiating with Mr. Starr to arrange a means of testifying short of appearance in person. As he's done before, the president could tape answers to questions. Some variation on this may prove acceptable to the independent counsel, particularly if he's eager to avoid a long battle over constitutional issues.
Those issues revolve around the question whether any arm of government, other than Congress with its impeachment powers, has the authority to compel a president to obey a subpoena.
Legal rulings of recent years - from the Watergate tapes decision to the more recent high court ruling allowing the Paula Jones lawsuit to go forward (until a lower court threw it out on other grounds) - don't favor the president. A federal court, rejecting executive privilege arguments, now has ruled that the president's counsel (a government-paid, not private, lawyer) must testify before Starr's grand jury.
Where questions of judicial process are concerned, the president, like any other citizen, is obliged to cooperate. The allegations against the president, perjury and suborning perjury, are serious, affecting the integrity of the justice system. Starr is attempting to build evidence that these crimes occurred. Whether such evidence is grounds for impeachment - that's an entirely different matter.
The president says he has done nothing illegal. He has an opportunity - a duty, in fact - to reaffirm that for the grand jury. History would suggest that any effort to evade that duty could lead to far greater "indignities."