Reproductive rights advocates vowed to challenge a move by Arkansas Secretary of State John Thurston, who on Wednesday disqualified a grassroots ballot initiative that seeks to enshrine abortion access in the Arkansas Constitution. Thurston argued that the group behind the proposed ballot amendment, Arkansans for Limited Government, failed to identify paid canvassers, tossing 14,000 of the more than 100,000 signatures collected. Voters in nearly a dozen states could see abortion-related amendments on the ballot in November.