It's not just Ted Cruz, John Kasich and Donald Trump in Indiana.
There was also a visit this week from Libertarian presidential candidate Gary Johnson.
He's the former governor of New Mexico and is suing the Presidential Debate Commission.
Johnson says the Commission keeps the debates exclusive.
“At the heart of what’s wrong with presidential politics is the Presidential Debate Commission, made up of Democrats and Republicans,” he says. “They collude with one another to exclude everybody else.”
Johnson last ran for president in 2012.