For the first time since the impeachment trial of then-President Bill Clinton, the Senate is formally planning a closed-door session that will allow Senators to have a frank, off-the-record discussion about how intelligence was handled in the run-up to the war in Iraq.

Majority Leader Bill Frist (R-Tenn.) and Minority Leader Tom Daschle (D-S.D.) reached a final agreement on holding the executive session on intelligence Thursday night, after Democrats threatened to force the unusual procedure on their own.

“Daschle and Frist have come to an agreement that this is something they will do in the future, but no details have been agreed to,” said Amy Call, spokeswoman for Frist.

While no date and format have been agreed on, executive sessions of the Senate require that all staff save for a handful of key aides clear the chamber, and the galleries are emptied of spectators and press. C-SPAN cameras are turned off, and the few aides who remain in the chamber must sign a document swearing themselves to secrecy, punishable by contempt charges.

Democrats are pushing for the rare session to be held shortly after the Senate returns from the Presidents’ Day recess. “The sooner, the better,” one senior Democratic aide said.

But a GOP aide suggested that it could be a few weeks or longer before the closed-door session is held because the Intelligence Committee last week agreed to expand its ongoing investigation into the pre-war intelligence handling and statements by Bush and Clinton administration officials regarding Iraq’s possession of chemical weapons.

The aide suggested that if the Intelligence Committee did some more work on the matter, there might be more facts known about the issue and make for a better, fuller discussion in the executive session.

To some degree, Senate leadership agreed to hold the executive session — which Democrats began pushing for earlier this month — because they realized that the rules of the chamber allowed for the Democrats to force the issue, with any two Senators capable of forcing a session, aides said.

By embracing the issue, rather than letting the Democrats force the matter, Frist and GOP leaders can take an active role in setting the agenda for the session. A Democratic aide said that one proposal called for a four-hour session, with time equally divided between the two parties.

Democrats hope that the session will create a sense of drama and urgency regarding President Bush’s pre-war claims that Iraq had weapons of mass destruction, something that has not been backed up to date.

Some of these issues will fall under the scope of the Intelligence Committee’s new probe, giving Republicans a chance to delay.

The session would be just the 54th closed executive session since 1929. The last time the Senate met in closed session was a four-day stretch five years ago, from Feb. 9 to Feb. 12, to act as a jury debating the four articles of impeachment against then-President Clinton. In that instance, no transcripts were kept, although some Senators opted to release their statements.

Other closed sessions have tended to focus on grave foreign policy questions, such as the 1997 vote on the chemical weapons treaty. The House has held just four closed executive sessions in its history.