HELENA, Mont. – Ted Cruz’s presidential campaign is trying to knock Republican opponent John Kasich out of Montana’s June 7 primary by questioning the signatures the Ohio governor’s campaign submitted to qualify for the ballot.

The Cruz campaign asserts that Kasich’s petition to be placed on the ballot contains signatures with invalid notaries, improper dates, mismatched phone numbers, illegible names, among other potential discrepancies.

The campaign hasn’t officially contested the signatures by filing a lawsuit. The ballots are to be printed by mid-April.

Montana Secretary of State Linda McCulloch says Kasich’s name will remain on the ballot unless a judge orders otherwise.

Greg Frank, who co-chairs the Kasich’s Montana campaign, stands by the validity of the signatures, many of which he collected himself. He calls the effort to bounce Kasich from the ballot as “dirty politics.”