Following Justice David Souter's retirement announcement, pundits of all stripes came to a common conclusion: it just doesn't matter. Given Souter's reputation for voting with the liberal block on the Court, many believe that the vacancy created by his retirement produced a zero-sum game - one in which one liberal voice on the court would be replaced with another liberal voice.

But such thinking is too simplistic. Justice Souter's record demonstrates that he was a swing vote - sometimes the decisive fifth vote - in numerous important cases. There is therefore a genuine risk that the center-left Justice Souter could be replaced with a far-left Obama nominee.

While Justice Souter disappointed conservatives who hoped for a justice who would adhere to originalism - that is, a justice who would apply the laws and Constitution according to their plain and original meaning rather than according to policy preferences or the elite opinion of the day - he nonetheless eschewed the excesses of judicial activism in favor of the demands of rule of law in numerous cases touching issues like lawsuit abuse and criminal law.

In the area of lawsuit abuse, Justice Souter provided the fifth vote just last term in a majority opinion in the Exxon case, which limited excessive punitive damages under maritime common law. Punitive damages are a favorite weapon of trial lawyers, who greeted Souters opinion with some disdain.

Another blow to the trial lawyers came in a Souter decision authored in 2007, in which he again cast the decisive fifth vote in an antitrust case holding that a plaintiff initiating a lawsuit can't make a naked accusation but must lay forth facts that "raise a reasonable expectation" that he has a right to relief. This struck a major blow against trial lawyer suits amounting to fishing expeditions, in which lawyers bring a lawsuit without any factual basis, and then rely on the liberal rules of discovery to force a settlement to avoid pre-trial and trial costs.

In the area of criminal law, Souter has departed from the views of his more liberal brethren in numerous cases. For example, in Arizona v. Fulminante, Souter again cast the decisive fifth vote, finding that appeals courts need not throw out every conviction where an involuntary confession is admitted, but should consider whether there was more than enough other evidence presented to the jury to allow a reasonable person to conclude that the accused was guilty even in the absence of the confession. This principle, known as harmless error, is generally applied in criminal law, and prevents those who are clearly guilty from being freed due to law enforcement errors - an unremarkable proposition that nonetheless generated a 5-4 vote.

Additionally, Souter has shown reasonable deference to the police, holding that the Constitution does not prevent a police officer from ramming his patrol vehicle into the car of a fleeing suspect to put an end to a dangerous high-speed car chase. Surprisingly, Justice Stevens in dissent was willing to second guess the judgment of the police based upon his viewing of a chase video, and his own assessment of risk to bystanders.

Souter has also shown some restraint in the context of the Eighth Amendment, joining an opinion holding that the sentence of life without the possibility of parole for possession of a large quantity of cocaine did not violate the Cruel and Unusual Punishments Clause - and prudently recognized the basic principle that judges should generally defer to legislatures' determinations of the appropriate punishment for a criminal offence. He provided the fifth vote for the position that the Fourth Amendment does not restrict a warrantless arrest for minor misdemeanor violations.

These are but a few of the cases in which Souter departed from the activist positions of his colleagues, and often did so as the deciding vote.

Given these cases, President Obama's statements on Friday about the kind of judge he is seeking are all the more disturbing. In discussing how he would choose a judge, he returned to his favored refrain, promoting "understanding and identifying what people's hopes and struggles [are] as an essential ingredient for arriving at just decisions and outcomes . . ."; These words suggest a drastic change in the courts - one in which lady justice is stripped of her blindfold in order to choose winners and losers not based on what the law requires, but based on how she feels about the parties before her. This is a recipe not for a center-left jurist, but for a far-left judge ready to do the bidding of hard line liberals, not just on social issues like gay marriage, but on issues of crime and punishment and trial abuse.

Obama should seek judges who will apply the law as it was written, not how they would like it to be written to address the particular parties before them. To do otherwise in replacing Souter will surely shift the Court further to the left, and further away from the rule of law.

Robert Alt is a senior legal fellow and deputy director of the Center for legal and Judicial Studies at The Heritage Foundation (heritage.org).