Here are excerpts from some articles:
In early October, Lott had advanced the date of the Republican leadership elections from early December to November 18 and began aggressively seeking support for his re-election as the Republican leader. Nickles decision not to run came days after Lott disclosed he had garnered enough support to guarantee his re-election. (Makes it sound as if Lott was able to set the election date for ML by himself.)
U.S. Senate Minority Leader Trent Lott (R) of Mississippi has advanced the date of the Republican leadership elections from early December to November 18. This is believed to be a bid to flush out and limit the time potential rivals will have to mount a campaign against the Republican Leader. U.S. Senator Don Nickles (R) of Oklahoma, who will step-down as Minority Whip at the end of this session, is rumored to be a likely candidate to challenge Lott. (From Gannett newswire)
From Robert Novak:
Sen. Trent Lott disregarded senatorial travel schedules when his staff let out the word that he plans to hold the Senate Republican leadership's election in mid-November instead of early December as scheduled, a change that might make it harder to replace him as Senate Republican leader. The problem is that two major congressional overseas trips conflict with Lott's new election date of Nov. 18. At that time, several senators are planning to attend the NATO meeting bringing in new members of the alliance, and the powerful Sen. Ted Stevens is taking fellow appropriators on a global inspection trip.
An earlier election date would give Sen. Don Nickles, now the deputy majority leader, less time to mount a challenge against Lott.
And from Roll Call:
"In a surprise move, Senate Minority Leader Trent Lott (R-MS) has abruptly advanced the date of Republican leadership elections by several weeks in what some GOP insiders believe is a bid to force the hand of Sen. Don Nickles (R-OK)," Roll Call reports. "There has been widespread speculation that Nickles will run against Lott for the top Republican spot, although the Oklahoman is keeping his own counsel about his plans."
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I'll have to do some more research tomorrow. What I don't know now is if the Majority Leader can call for an election at any time, or if he needs to have unanimous consent to do so. Lott may have worked to get the votes, given some favors out, and had the 26 votes to win, wanted to set the election early, and the senators knowing this, all voted to set the election early because they knew no one else could win. The Senate is really arcane...