By the way, the USCCB voting guide is precisely in line with this:
- Decisions about political life are complex and require the exercise of a well-formed conscience aided by prudence. This exercise of conscience begins with outright opposition to laws and other policies that violate human life or weaken its protection. Those who knowingly, willingly, and directly support public policies or legislation that undermine fundamental moral principles cooperate with evil.
…]
- Catholics often face difficult choices about how to vote. This is why it is so important to vote according to a well-formed conscience that perceives the proper relationship among moral goods. A Catholic cannot vote for a candidate who takes a position in favor of an intrinsic evil, such as abortion or racism, if the voter’s intent is to support that position *). In such cases a Catholic would be guilty of formal cooperation in grave evil. At the same time, a voter should not use a candidate’s opposition to an intrinsic evil to justify indifference or inattentiveness to other important moral issues involving human life and dignity.
- There may be times when a Catholic who rejects a candidate’s unacceptable position may decide to vote for that candidate for other morally grave reasons *). Voting in this way would be permissible only for truly grave moral reasons, not to advance narrow interests or partisan preferences or to ignore a fundamental moral evil.
Link:
usccb.org/issues-and-action/faithful-citizenship/forming-consciences-for-faithful-citizenship-part-one.cfm
*) Compare with Ratzinger’s (the current Pope’s) statement:
"A Catholic would be guilty of formal cooperation with evil, and so unworthy to present himself for Holy Communion, if he were to deliberately vote for a candidate precisely because of the candidate’s permissive stance on abortion or euthanasia. When a Catholic does not share the candidate’s stance in favor of abortion or euthanasia, but votes for that candidate for other reasons, it is considered remote material cooperation, which can be permitted in the presence of proportionate reasons.