Fitzgerald had to indict Libby. Libby's lies were so blatant that Fitzgerald had no choice. But Fitzgerald had a golden opportunity to do enough work to prove the underlying crimes that he was originally investigating. Those crimes involve two offenses in the U.S. Criminal Code; Conspiracy and Outing a CIA agent. Essentially Fitzgerald indicted Libby for preventing his prosecutors from proving the underlying crimes he was investigating by using a baseball metaphor in that Libby "threw sand in the umpires eyes." That part is patently absurd.
In most conspiracy cases, one or more of the co-conspirators invariably lie to the FBI or the Grand Jury. That is something that prosecutors face all the time. The idea that Libby alone prevented Fitzgerald from proving the underlying crime is absurd. If Cheney told Libby about Valerie Plame, there obviously was a reason. The idea that Cheney, Libby, Rove and Bush did not talk to each other about the purpose of passing on this information to the press is simply not believable. And there were many ways that Fitzgerald could have proven the conspiracy in spite of Libby's lies. The fact that Libby lied would normally embolden a prosecutor to prove the underlying crime. This was not the case for Fitzgerald.
Fitzgerald stated in his press conference that most of his work has been completed. While there is always a Grand Jury available to indict others in the event of an unlikely plea bargain for Libby, the investigative phase is really over for this prosecutor. His office will now focus on the trial of Libby. Those of us who know about prosecutors and Grand Jury investigations would tell you that Fitzgerald, using a baseball metaphor, threw the Bush ka bal a "softball." And using a football metaphor, he "fumbled the ball."