Is Frist Making Legislative History??

This from the Washington Post:

Senate Majority Leader Bill Frist signaled yesterday that he and other White House allies will filibuster a bill dealing with the interrogation and prosecution of detainees if they cannot persuade a rival group of Republicans to rewrite key provisions opposed by President Bush.

I can't remember another time when the Senate majority leader has threatened a filibuster. Admittedly, I'm not an expert on congressional history. Does anyone know of an earlier precedent for this? Is this event what it appears to be, an indication that the party leadership has completely lost control?

Addendum

My colleague Anne Joseph, who is a student of congressional affairs, raises an interesting question::

if here, why not stem cells? Similar political dynamics, but Frist, if I recall correctly, did not threaten a filibuster. A quick search reveals one report that Frist did, at least, "consider" a filibuster on the recent stem cell legislation. (here)

Another thought (this time from me rather than Anne): Frist's threat could be related to his presidential ambitions rather than any immediate need to kill the McCain bill. But to the extent that this event is unusual, presidential ambition can't be the full explanation. First, Frist isn't the first Senate majority leader to have had such ambitions. Second, the majority leader should be able to prevent a vote on legislation with something less clumsy than a fillibuster threat. Does Frist lack enough party support to use these other tools (a very bad sign for his leadership if true)? Or does the fillibuster threat make a better statement to the conservative base he hopes to cultivate for the nomination?