INDIANAPOLIS (AP) — Republican presidential front-runner Mitt Romney's Indiana co-chairman could decide whether opponent Rick Santorum makes it onto the state's May primary ballot.

Dan Dumezich is guiding Romney's effort to win Indiana and also runs the state elections panel that weighs challenges to candidates' ballot access. Santorum is eight signatures shy of the 500 needed from Indiana's 7th District.

Registered voters have until Friday to file challenges to a candidate appearing on the ballot. The four-member bipartisan Indiana Election Commission would then have to make a decision by March 1.

Dumezich says he has no plans to recuse himself from a vote if Santorum's access is challenged.

Indiana's signature requirement has also put Republican gubernatorial candidate Jim Wallace in danger of not making the ballot.