Support for gay marriage “seriously harm(s) their communion with Christ and His Church,” Archbishop John Myers wrote in a pastoral letter.
Washington, Maryland and Maine will vote on marriage equality in November.
Minnesota is voting on a state constitutional amendment, backed by more than $1 million in Catholic Church money, that would enshrine marriage as between a man and a woman.
Seattle’s Catholic Archbishop J. Peter Sartain has written letters and recorded a video espousing Church dogma and urging a “No” vote on Referendum 74.
But neither Sartain nor fellow bishops have questioned the faith or threatened to penalize those who disagree with them.
Myers showed no restraint in his lengthy letter.
“I urge those not in communion with the Church regarding her teachings on marriage and family . . . sincerely to reexamine their consciences,” wrote the Archbishop.
“If they continue to be unable to assent to or live Christ’s teachings in these matters, that they must and in all humility refrain from receiving Holy Communion until they can do so with integrity,” Myers wrote.