[Campion]

In the comments, from the Congregation for the Doctrine of the Faith:

In those situations where homosexual unions have been legally recognized or have been given the legal status and rights belonging to marriage, clear and emphatic opposition is a duty. One must refrain from any kind of formal cooperation in the enactment or application of such gravely unjust laws and, as far as possible, from material cooperation on the level of their application. In this area, everyone can exercise the right to conscientious objection.

[Salvation]

Thanks for that.