The measure, which would allow refusal of wedding-related services to same-sex couples on religious grounds, has problematic wording, says the Senate president.
The ruling was accompanied by a stay, meaning same-sex couples can not yet begin marrying in Virginia.
Lay Catholics from Florida to Germany ask the church to change on same-sex relationships.
The civil rights attorney was honored at the Makers conference this weekend.
LGBT organizations are taking aim at discriminatory marriage laws in two traditionally conservative states.
The couples challenging the ban want it suspended while they await a trial in the case.