The state chapter of the American Civil Liberties Union filed a legal challenge intended to knock a proposed state constitutional amendment gay marriage in Arkansas off the November ballot. The proposed amendment would prohibit state recognition of civil unions between same-sex couples. The ACLU says the measure is vaguely worded by design and that it is crafted to hide it`s potentially far-ranging effects on civil unions, single people and heterosexual married couples. The group wants an expedited hearing before the state Supreme Court. Backers of the amendment say they were prepared for a legal challenge. The ACLU filed the complaint on behalf of a heterosexual couple and a gay man, Bill Bradford of Little Rock. The 76 year old Bradford says he was denied survivor benefits when his partner of 56 years died. Bradford said he`d favored the proposed amendment until he understood its implications.