Louisiana voters have overwhelmingly approved a state constitutional amendment banning same-sex marriages and civil unions. Nearly all of the precincts report that nearly 80 percent of voters supported the ban. New Orleans was the only area to show a close race. The city is home to a politically strong gay community. But even there, the amendment was passing by a slight margin. The civil rights group Forum for Equality has already promised to challenge the ban in court. Christian conservatives led a grassroots campaign lobbying for the amendment.