SENATE AGREES ON TRIAL SETUP.

Byline: Alison Mitchell The New York Times

After an extraordinary bipartisan caucus that lasted about three hours, the Senate voted unanimously Friday to approve a plan for President Clinton's impeachment trial that calls for opening arguments next week and defers a decision on whether to summon witnesses until later in the month.

The agreement averted further confrontation over rival Republican and Democratic trial plans that had threatened to send the Senate into the same partisan spiral as the House. The two sides had been deeply divided over whether to allow witnesses.

In a brief session presided over by Chief Justice William Rehnquist late Friday afternoon, the senators approved the plan they had outlined earlier in the Old Senate Chamber, where the Senate had met throughout the early 19th century.

An official summons directing Clinton to respond to the two articles of impeachment against him was delivered to the White House by James Ziglar, the Senate sergeant-at-arms.

Although some Democrats were wary of the blueprint, many senators from both parties reveled in institutional pride at maintaining a conciliatory tone that had eluded the House.

``You know, we didn't ask for this trial,'' said Sen. Patrick Leahy, D-Vt. ``We didn't ask for the president to conduct himself the way he did, and we didn't ask for the House to make a mishmash of this thing. But all that's happened, and now we have to preserve the Senate and give the country a sense of credibility.''

Sounding the same note, Sen. Mitch McConnell, R-Ky., said, ``I think there's a feeling in this situation that the Senate is on trial.''

The White House, in a terse, carefully worded statement, said Friday afternoon that it respected the Senate's decision. ``In accordance with the procedures adopted by the Senate, we plan to present on behalf of the president a vigorous, successful and complete defense,'' said Gregory Craig, the special White House counsel, at an appearance in the White House driveway.

The White House had hoped the Senate would settle on an abbreviated trial without witnesses, confined to the material submitted by Kenneth Starr, the independent counsel. White House aides waited anxiously while the senators met privately Friday, and some acknowledged disappointment at the procedure that emerged.

But Craig said the White House was confident that the Senate would move to cut off the proceeding after the opening presentations, rather than extend the trial and call witnesses. ``We remain hopeful that this matter can be resolved expeditiously and fairly,'' he said, before turning his back and walking away from reporters' shouted questions.

Under the Senate plan approved Friday, the trial of Clinton on charges of perjury and obstruction of justice stemming from his efforts to hide his affair with Monica Lewinsky would get under way in earnest Wednesday with arguments on any procedural pretrial motions by House prosecutors or White House lawyers.

Beginning the next day, the House has 24 hours to present its case against the president. Clinton's legal team follows with its allotted 24 hours. Both sides are precluded from introducing new evidence unrelated to the impeachment record established in the House.

Senators then will have 16 hours to question the two sides by sending written queries to Rehnquist, who will be in the presiding officer's chair at the front of the chamber.

At that point - expected to be either Jan. 25 or Jan. 26 - senators plan to debate and vote on two separate motions, one to adjourn the trial and the other on whether to call witnesses. Those votes would be simple majority votes.

If witnesses are approved, the House prosecutors or the White House would question them first in a deposition. Sen. Tom Daschle, the minority leader, said a second majority vote would be required to have witnesses testify before the full Senate.

Democrats, who had previously stood adamantly against witnesses, are taking solace in the fact that witnesses would have to be approved en masse, which they believe would discourage the House from seeking to call too many witnesses. They also anticipate that the senators, sitting as jurors under a vow of silence, will have a diminishing appetite for witnesses after listening to the House and White House for two weeks.

``There's one thing the Senate can't tolerate, and that's remaining quiet for very long,'' said Sen. Christopher Dodd, D-Conn. ``And the idea they are going to sit there day after day and listen to House managers and White House counsels, with their inability to respond, is not going to last very long.''