Microsoft CEO Steve Ballmer is not only an apish buffoon, but he also apparently lacks a backbone. It was revealed today in a letter to Yahoo shareholders written by “activist investor” Carl Icahn that Ballmer expressed fears that the current Yahoo board—hostile to a takeover by Microsoft—could put the huge bounty needed for the acquisition into question.

“If and when a transaction is consummated,” Icahn’s letter states of Ballmer’s acquisition logic, “Microsoft would be guaranteeing a great deal of capital at closing. However, a transaction could take at least nine months and perhaps longer to obtain regulatory clearance in the U.S., Europe and elsewhere.” During that period, his thinking goes, if the current board and Yahoo management team “mismanage the company (and their recent track record is far from reassuring), Microsoft would be putting its money a risk and a great deal could be lost.”

So it’s the board’s fault—not Ballmer’s own ineptitude—that caused the original negotiations to go south. “Microsoft would be willing to enter into discussion immediately if the new board that has been nominated is elected,” a board that just happens to include the name Carl C. Icahn. “I do not as yet represent the Yahoo board,” Icahn wrote, but strongly believes that the new board would “be presenting shareholders either a purchase offer for the whole company or a very attractive offer to purchase ‘Search’ with large guarantees.” He added that the current board “botched up” negotiations by not immediately taking Microsoft’s offer of US$33 per share.

Of course, Yahoo’s board is not without its own foibles. For the past two years, the company’s income from operations has dropped 21 percent per year while Google’s has grown by 59 percent per year. Yet Yahoo’s board continues “paying itself $10,000 per week,” asserts Icahn. He also takes the opportunity to slam Yahoo's CEO, calling for a new board that would “replace Jerry Yang with a new CEO with operating experience.”

Never a dull moment.