Scholars have identified serious drawbacks to the independent state legislature (ISL) claim, which precludes state-court review of election laws, thus preventing state guarantees like “free and fair elections” from being enforced. Considering its flaws, we ask why ISL would be pursued so fervently and why the Supreme Court, in Moore v. Harper, adopted a version of it. Examining data that compare election-law outcomes in federal and state supreme courts, we found that state supreme court justices, even if Republican, are not reliable supporters of the GOP electoral agenda. The Roberts court, by contrast, has voted in the GOP-supported direction in most election-law cases it has decided. This, we argue, is why ISL is promoted so vigorously: it takes electoral disputes—such as who can vote, what the rules for counting are, and such—out of the hands of state courts and places them squarely into the hands of the Supreme Court, a reliable partisan ally.