Do campaign contributions affect judicial decisions by elected judges in favor of their contributors’ interests? Although the Supreme Court’s recent decision in Caperton v. A.T. Massey Coal Co. relies on this intuition for its logic, that intuition has largely gone empirically untested. No longer. Using a dataset of every state supreme court case in all fifty states over a four-year period, we find that elected judges are more likely to decide in favor of business interests as the amount of campaign contributions received from those interests increases. In other words, every dollar of direct contributions from business groups is associated with an increase in the probability that the judge in question will vote for business litigants. Surprisingly, though, when we disaggregate partisan and nonpartisan elections, we find that a statistically significant relationship between campaign contributions and judicial decisions in favor of contributors’ interests exists only for judges elected in partisan elections, and not for judges elected in nonpartisan ones. Our findings therefore suggest that political parties play an important causal role in creating this connection between campaign contributions and favorable judicial decisions. In the flurry of reform activity responding to Caperton, our findings support judicial reforms that propose the replacement of partisan elections with nonpartisan methods of judicial selection and retention.