Massachusetts is one of the most Catholic states and also one of the most Democratic with no Republicans in its U.S. congressional delegation.
O'Malley acknowledged that he disagrees with many Republicans on a wide range of issues, from immigration to capital punishment, The Boston Globe reported. But he suggested that abortion should be a primary issue for Catholic voters and called the Democratic Party "extremely insensitive to the church's position."
"I think that, at times, it borders on scandal as far as I'm concerned," he said of voting patterns in his diocese.
He called on Catholics to "actively dissociate" themselves from politicians who don't oppose abortion, the Globe said.
O'Malley was attending the Catholic Bishops Conference. The bishops adopted a document Wednesday that urged Catholics to consider a range of issues in the voting booth, including abortion.