Jan. 20, 2012 - West Palm Beach, Florida, U.S. - - WEST PALM BEACH - Members from local communities and advocacy groups express their opposition to the U.S. Supreme Court's decision in Citizens United v. Federal Election Commission during a demonstration Friday afternoon outside the federal courthouse in West Palm Beach. The event was one of many events that took place around the nation on Friday, and local efforts were organized by Move to Amend and the Occupy movement.(Credit Image: © Brandon Kruse/The Palm Beach Post/ZUMAPRESS.com)

If President Barack Obama or a future Democratic successor were to replace late Supreme Court Justice Antonin Scalia with a liberal, a host of prior high court decisions that favored conservatives could be revisited, and possibly be overruled completely.

The reach of cases that could get another look by a liberal majority Supreme Court touch on bedrock issues of American life, such as race, religion, voting rights, campaign finance, and the Second Amendment.

While it is normal practice for the Supreme Court to rule again on law it already settled, legal experts say the outcome of such an effort if a liberal justice replaced Scalia would be especially dramatic. Indeed, a move from Scalia, a staunch conservative, to a liberal would be the largest ideological shift in the court since 1991, when Thurgood Marshall retired and was replaced by Justice Clarence Thomas.

“The Supreme Court can decide we got a past decision wrong, they absolutely can,” said John Malcolm, the director of The Heritage Foundation’s Meese Center for Legal and Judicial Studies. “And they have done that. Every term they will typically overturn one or two of their prior precedents.”

“If a liberal were to replace Justice Scalia, any case that was a 5-4 decision in which Scalia was in the majority is potentially vulnerable, and there are a lot of very important cases that are in that category,” Malcolm continued. “The stakes in choosing the next justice are extremely high.”