With four justices in their seventies and Justice John Paul Stevens now 88, it's almost a given that the next president will exercise the power to put his mark on the makeup of the Court. Barack Obama says he will appoint empathetic justices who understand the struggles Americans face.

From his days as president of the Harvard Law Review and as constitutional law professor at Chicago Law School, Sen. Barack Obama is well-versed in various judicial philosophies and what's required of a top-notch jurist. His vision of that ideal person is something he articulated in a speech to Planned Parenthood in July 2007: "We need somebody who's got the heart, the empathy, to recognize what it's like to be a young teenage mom. The empathy to understand what it's like to be poor, or African-American, or gay, or disabled, or old. And that's the criteria by which I'm going to be selecting my judges."

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But Obama supporter and fellow Senate Judiciary Committee member Ben Cardin (D, MD) says his party's presidential nominee hasn't laid out any non-negotiable criteria for potential nominees.

"There's no one thing that would qualify or disqualify you from being a nominee. We're looking for a person who has respect for the Constitution. A person who will look at the previous interpretations," said Cardin.

Obama says he is committed to respecting the Constitution, but also believes that it must be viewed from the context of 2008.

"His view is that our society isn't static and the law isn't static as well. That the Constitution is a living and breathing document and that the law and the justices who interpret it have to understand that," said Melody Barnes, senior domestic policy adviser for the Obama campaign.

Voters can also glean a bit more information about Obama's judicial philosophy by taking a look at how he feels about those who now sit on the Court. Of Justice Clarence Thomas, Obama says he wasn't a strong enough jurist or legal thinker at the time of his nomination. And when it comes to the Court's newest additions, Chief Justice John Roberts and Justice Samuel Alito, Obama voted against confirming both.

"There's nothing wrong with voting against nominees who don't appear to share a broader vision of what the Constitution is about," Obama said last July to Planned Parenthood, a position he has reiterated many times since.

Cardin agreed with the assessment. "What we have seen is that both have been activists. Both look for ways of changing the precedent of the previous rulings, of weakening the constitutional protections, of enlarging the powers of the president."

The eternal conflict between the White House and Capitol Hill is something Obama made a point of bringing up during his August appearance with Pastor Rick Warren at the Saddleback Church.

"One of the most important jobs of, I believe, the Supreme Court, is to guard against the encroachment of the executive branch on the other, the power of the other branches," he said.

Obama also complained that Chief Justice Roberts has been too acquiescent to the demands of the president. "I think he has been a little bit too willing and eager to give an administration, whether it's mine or George Bush's, more power than I think the Constitution originally intended."

Instead, Obama's camp says his priorities for nominees will be those who have a strong sense of social and economic justice and elitist judges who will leave ordinary Americans to fend for themselves.

"He's looking for someone who brings empathy to the Court," said Barnes, "who understands the importance of whether or not the justice is going to make sure there is a level playing field for the powerless, as well as for the powerful. Making sure that the individual interests as well as the business interests are interpreted fairly. Whether or not the courthouse door is going to remain open to people. Whether or not it's going to be slammed shut."