A Black Hawk resident trying to win the U.S. Senate seat being vacated by retiring Tim Johnson can't be on the general election ballot.
Secretary of State Jason Gant on Tuesday said independent candidate Clayton Walker won't be on the ballot after his nominating petitions were successfully challenged.
Walker can appeal the decision in circuit court.
Gant in a letter sent to Walker said the challenge left the candidate 1,410 signatures short of the 3,171 required for his petition to remain filed.
Brookings resident Mary Perpich contested the petitions. She's the Brookings County Democratic Party chairwoman.
Walker's petitions were challenged on the grounds that they included unregistered voters, had discrepancies in the counties and addresses listed for the signers and showed information difficult to verify because of their "poor quality."