In the runup to every election, politicians wait in hopeful or nervous expectation of the "October surprise" -- a last-minute news bombshell that can turn the electoral tide. In 1980, Republicans feared that the Carter administration would bring U.S. hostages held in Iran home prior to the election, and therefore avert the looming Reagan landslide. In 1992 Iran-Contra prosecutor Lawrence Walsh indicted top Reagan administration officials just before the election. This year also had its October surprise, though it came from a most unexpected quarter.

Or quarters. First, gravediggers around Monticello have purportedly confirmed that Thomas Jefferson, third president of the United States, did indeed father an illegitimate child with his slave, Sally Hemings, as Jefferson's political opponents and some of his biographers had long alleged. In the year of Monica, this is supposed to be a significant finding. If Jefferson could do such a thing to his slave, it is argued, surely Mr. Clinton can be forgiven for doing similar to his servant.

Second, and more significant, is a full-page advertisement that ran in the New York Times under the banner headline "Historians in Defense of the Constitution." The ad was preceded by the customary news conference (this one featuring the redoubtable Arthur M. Schlesinger Jr.), but it was not until last Friday, four days before the election, that the ad appeared. There it was announced (apparently for the benefit of the voters still in doubt) that the "vote of the House of Representatives to conduct an open-ended inquiry creates a novel, all-purpose search for any offense by which to remove a President from office," and that the "theory of impeachment underlying these efforts is unprecedented in our history {and} if carried forward, they will leave the Presidency permanently disfigured and diminished, at the mercy as never before of the caprices of any Congress."

Familiar charges, these, but this time they come not from the White House or its Hollywood friends, but from more than 400 professional historians, many of them well-known, some of them distinguished and none of them (we are to believe) partisan. "We do not condone President Clinton's behavior or his subsequent attempts to deceive," they say, but "the current charges against him depart from what the Framers {of the Constitution} saw as grounds for impeachment." Except for one reference to a commonplace uttered by James Madison, we have only their word on this, but their word ought to carry weight, coming as it does from professors at all the Ivy League universities (save only Dartmouth), along with Stanford, Chicago, Virginia, Duke, Berkeley, Williams, Amherst and many lesser institutions.

The fact is, however, that they are mistaken about the grounds for impeachment -- so obviously mistaken that one can doubt that any of them ever looked into this matter before they made their pronouncement.

The grounds for impeachment (see Article II, Section 4 of the Constitution) are "Treason, Bribery, or other high Crimes and Misdemeanors," and they are the same for everyone subject to it, the president, vice president and "all civil Officers of the United States." The "current charges" against the president -- or, at least, those now being considered by the House Judiciary Committee -- are three in number: "providing false and misleading testimony under oath in a civil deposition and before the grand jury," "withholding evidence and causing evidence to be withheld and concealed" and "tampering with prospective witnesses in a civil lawsuit and before a federal grand jury."

On the face of it, these would seem to be serious offenses, and the first of them especially is amenable to proof or disproof. But, since they obviously have nothing to do with treason or bribery, the issue is whether they belong in the category of "high Crimes and Misdemeanors." The historical record casts some light on this.

In 1803, John Pickering, a federal judge, was impeached and convicted for "appear{ing} on the bench . . . in a state of total intoxication {where he} did then and there frequently, in a most profane and indecent manner, invoke the name of the Supreme Being, to the evil example of all the good citizens of the United States." If drunkenness and impiety, why not perjury?

Then, in 1868, President Andrew Johnson was impeached (but acquitted)for "utter{ing} loud threats and bitter menaces as well as against Congress as the laws of the United States duly enacted thereby, amid the cries, jeers, and laughter of the multitudes then assembled and within hearing." If this (call it what you will) is a high crime or misdemeanor, why not tampering with witnesses?

Mr. Clinton's defenders -- but not these historians, who say nothing about it -- insist that by "high Crimes and Misdemeanors" the Framers meant only those offenses that, unlike Judge Pickering's drunkenness on the bench or President Johnson's harangues, affect the political or constitutional order. But this is clearly not the case. The record makes it absolutely clear that impeachable offenses, in addition to those of a political character, were understood to include ordinary crimes, crimes that might well be committed by private as well as public people and would be tried in the regular courts.

We know this from what was said by Alexander Hamilton (in Federalist 65), by Luther Martin (during the impeachment trial of Justice Samuel Chase), by James Wilson (in his celebrated lectures on the law at what became the University of Pennsylvania) and by Joseph Story (in his authoritative "Commentaries on the Constitution"). As Story put it, "Crimes of a strictly legal character fall within the scope of the {impeachment} power."

This is clear from the Constitution itself. Article I, Section 3 stipulates as follows: "Judgment in Cases of Impeachment shall not extend further than to removal from Office, and disqualification to hold and enjoy any Office of honor, Trust, or Profit under the United States: but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law." The only cases in which both the Senate and the regular courts have jurisdiction are those involving serious statutory or common law crimes.

Since perjury, withholding evidence and tampering with witnesses are federal crimes, it follows, contrary to the judgment of those 400 historians, that the "current charges" against Bill Clinton do not "depart from what the Framers saw as grounds for impeachment." The historians are correct only when they say that impeachment of the president is a "grave and momentous step." So it is, but the Constitution not only permits it but, when warranted, requires it.

Mr. Berns is a resident scholar at the American Enterprise Institute. (See related letter: "Letters to the Editor: Four-Decade Battle in Pinkish Landscape" -- WSJ Nov. 5, 1998) (See related letter: "Letters to the Editor: Morality as a Vital Collective Standard" -- WSJ Nov. 9, 1998)