JEFFERSON CITY, Mo. (AP) — A federal lawsuit is challenging a decades-old Missouri law that limits the extent to which volunteers can provide ballot-booth help to people who have disabilities or are unable to read or write. The lawsuit filed Wednesday targets a 1977 Missouri law that says people can only provide voting assistance to one other person per election, unless they are election judges or immediate family members. The suit contends that violates the Federal Voting Rights Act. The lawsuit is the latest among dozens of cases challenging election procedures across the country. A similar lawsuit is pending against an Arkansas law.