In a scenario straight of of Grisham's "The Appeal" the A.T. Massey coal company, who lost a jury trial, made $3 million in campaign contributions to someone running for a seat on the West Virginia Supreme Court of Appeals. Given that much money, the outcome of the campaign was a foregone conclusion and their candidate won.
When the case arrived at the appellate court, the newly elected judge refused to step aside and then joined the majority in overturning the lower court's decision. Today, the U.S. Supreme Court said that this action violates the due process clause. The Court stated:
There is a serious risk of actual bias when a person with a personal stake in a particular case had a significant and disproportionate influence in placing the judge on the case by raising funds or directing the judge’s election campaign when the case was pending or imminent. The proper inquiry centers on the contribution’s relative size in comparison to the total amount contributed to the campaign, the total amount spent in the election, and the apparent effect of the contribution on the outcome. It is not whether the contributions were a necessary and sufficient cause of Benjamin’s victory.
Interestingly enough, the decision was only 5-4, indicating that four justices apparently think it's OK to buy a judge. Those four are Roberts, Scalia, Thomas and Alito.