FORTUNE — Carl Icahn today acknowledged that he will be unable to thwart Michael Dell’s attempts to take Dell Inc. DELL private, with Dell shareholders expected to approve the $25 billion deal this Thursday.

Icahn has been fighting the PC maker’s founder and CEO for months, and has become its largest outside shareholder with nearly a 9% stake. But he recently lost a key legal battle in Delaware, while shareholders appear swayed by an upwardly-revised buyout offer that would pay them $13.75 per share, plus a 13 cent special dividend.

From a letter Icahn sent this morning to Dell shareholders:

We have determined that it would be almost impossible to win the battle on September 12th. We have therefore come to the conclusion that we will not pursue additional efforts to defeat the   Michael Dell/Silver Lake proposal, although we still oppose it and will move to seek appraisal rights.

I realize that some stockholders will be disappointed that we do not fight on.  However, over the last decade, mainly through “activism” we have enhanced stockholder value in many companies by billions of dollars.  We did not accomplish this by waging battles that we thought we would lose.  Michael Dell/Silver Lake waged a hard fought battle and according to Chancellor Strine, the actions by Dell were within the Delaware law.  We therefore congratulate Michael Dell and I intend to call him to wish him good luck (he may need it).

But Icahn didn’t pull all of his punches. Instead, he kept up his rhetorical assault against Dell’s board of directors, whom he has accused of doing everything in their power to make sure that Michael Dell emerges victorious:

We jokingly ask, “What’s the difference between Dell and a dictatorship?” The answer: Most functioning dictatorships only need to postpone the vote once to win… The Dell board, like so many boards in this country, reminds me of Clark Gable’s last words in “Gone with the Wind,” they simply “don’t give a damn.” 

As this long saga winds down, it is worth noting two things: (1) Icahn did play a positive role for Dell shareholders, getting Michael Dell to slightly increase a bid that had been viewed as “best and final.” (2) Icahn will make a small profit on Dell — or at least “small” by his billionaire standards. For example, in June he purchased 72 million shares from Southeastern Asset Management at $13.52 per share.

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