Legendary public defender Judy Clarke’s roster of reviled clients includes baby killer Susan Smith and Unabomber Ted Kaczynski, but Arizona shooter Jared Lee Loughner presents a formidable challenge. Gerald Shargel on her possible strategies, from the insanity defense to disqualifying all Arizona federal judges and prosecutors from the case. Plus, full coverage of the Arizona shooting.

No matter how heinous the crime, no matter how despicable the circumstances, Jared Lee Loughner is constitutionally entitled to an effective and zealous advocate singularly committed to providing him with the best possible defense. Loughner’s Sixth Amendment right to such representation has been fully satisfied with the appointment of Judy Clarke as his principal counsel, but Clarke has her work cut out for her.

Clarke is a legendary public defender with a national reputation largely fueled by a long roster of unpopular clients who have merited public obloquy—clients like Susan Smith, the South Carolina mother who drowned her two sons in 1994, 9/11 conspirator Zacarias Moussaoui, and the Unabomber, Ted Kaczynski. Defending clients with profiles both high and low, she is commonly praised as a serious, capable, and committed advocate. Following the Monday presentment of Loughner before a United States magistrate judge, USA Today gushingly described Clarke as a “One-Woman Dream Team.”

But however well suited Clarke is for the task, the challenge she now faces is formidable. The defense objective is readily apparent—every strategic decision must be geared toward the ultimate goal of saving Loughner from execution. Clarke knows that and has already advanced the chess pieces toward that end. The New York Times reported yesterday that all federal judges in Tucson have recused themselves from the case in light of the murder of their chief judge, John M. Roll. But Clarke went further, indicating that she was considering a motion to disqualify all Arizona federal judges and prosecutors from the case.

Judy Clarke, described by one New York lawyer who worked under her as a “master strategist,” has a keen eye on what may well dissuade Holder from pursuing the death penalty.

Under ordinary circumstances, federal cases eligible for the death penalty are sifted through a multistep process before the attorney general ultimately decides whether to seek such a penalty in a particular case. The first step in that process is a review and recommendation by the local United States Attorney’s Office handling the matter. That recommendation is then forwarded to the Justice Department, where a standing committee hears and considers presentations from both sides and then makes a recommendation to the attorney general.

While disqualification of all Arizona federal prosecutors may win a more objective assessment of the death-penalty issue at the local level, this is no ordinary case. Whether the first-round review is made by a biased Arizona federal prosecutor or a seemingly neutral federal prosecutor from Vermont, the bottom line is that the local-level decision to seek or not seek the death penalty is almost beside the point. In this highly politicized case, Attorney General Eric Holder, perhaps influenced by President Obama, will make the decision.

With a longer view toward Washington, it may be expected that Judy Clarke, described by one New York lawyer who worked under her at the San Diego Federal Defender’s Office as a “master strategist,” has a keen eye on what may well dissuade Holder from pursuing the death penalty. By all that has thus far been revealed, Loughner appears to be suffering from a severe mental disease or defect and seems to be particularly well suited to raise an insanity defense. In the past several days, both Clarke and the prosecutors have undoubtedly reached out to the nation’s leading forensic psychiatrists as well as percipient witnesses to offer opinions and shed light on Loughner’s mental condition.

But Clarke well knows what is commonly known among members of the criminal defense bar. At least since the 1981 shooting of President Reagan and the finding that would-be assassin John Hinckley was not guilty by reason of insanity, American juries have not responded well to the insanity defense, and it is now successful in only a small percentage of cases. To make matters worse, in the wake of the Reagan assassination attempt, Congress passed the 1984 Insanity Defense Reform Act, making the defense more difficult by requiring a defendant to prove that he was insane during the commission of the act.

Despite the difficulties attendant to an insanity defense before a jury, an opinion by one or more respected forensic psychiatrists concluding that Loughner was so mentally ill that he was “unable to appreciate the nature and quality or the wrongfulness of his acts” during the shootings may at least persuade Holder that the government should not pursue the death penalty. It would be a stunning victory for Clarke. With the death penalty off the table, the only unresolved issue to be tried or plea bargained would be whether Loughner is legally responsible for his acts, with the verdict or plea agreement determining whether Loughner spends the rest of his life in a prison or is committed to a hospital for the criminally insane.

Gerald L. Shargel, a member of the New York Bar since 1969, has handled numerous high-profile cases at both the trial and appellate level. He has written for The New York Times, the Los Angeles Times, the New York Law Journal, and Slate. Mr. Shargel, a Practitioner-in-Residence at Brooklyn Law School, recently authored a law review article published in the Fordham Law Review, "Federal Evidence Rule 608(b): Gateway to the Minefield of Witness Preparation."