McHugh & Callan Moral Theology §2643-4:

2643. The Duty of Exercising the Electoral Franchise.—(a) There is a grave duty of using the privilege granted to citizens of voting in public elections, and especially primaries; for the welfare of the community and the moral, intellectual and physical good of individuals depend on the kind of men who are nominated or chosen to rule, and on the ticket platforms voted for. Hence, those who neglect to vote coöperate negatively with a serious harm (viz., evil in power), or at least with public unconcern about public matters—for example, those who neglect through laziness or indifference to condemn by their vote. A grave inconvenience (e.g., sickness, ostracism, exile, persecution), but not a slight inconvenience (such as loss of time, trouble, ridicule), excuses from the duty; for an affirmative law has exceptions. Neither is there an obligation to vote when an election is a mere formality, as when there is but one candidate or party.

(b) The duty is not one of commutative justice, as the ballot is either a privilege, or a thing commanded by authority, but not a service to which the citizen has bound himself by contract or office. The obligation is, therefore, one of legal justice, arising from the fact that the common weal is everybody's business and responsibility, especially in a republic. Hence, representatives of the people who by abstention from voting cause a serious damage which they were bound ex officio to prevent, are guilty of commutative injustice and are held to restitution; but a citizen who stays away from the polls sins, and perhaps gravely, against legal justice, though there is no duty of restitution for the damages that result. Moreover, in a general election the vote of one citizen is usually not of decisive influence, and citizens do not make themselves responsible for all the acts of their representatives.

2644. Manner of Voting.—(a) Object.—It is not necessary to vote for the best candidate, provided one votes for a person who is fitted by character, ability, record, experience, etc. for the office, and gives indications, not merely promises, that he will serve the community well. But in certain ecclesiastical elections the voters must take oath beforehand to vote, not only for a worthy candidate, but also for the person whom they honestly think, all things considered, most worthy. In minor offices (such as constable or town clerk) it suffices that the candidate be known as conscientious; but in major offices (such as President, governor, congressman, legislator, or judge) the party principles for which he stands have to be considered chiefly. Per accidens, it is lawful to vote for an unworthy candidate when this is necessary to prevent a greater evil, as when the opposing candidate is much worse, or a good ticket cannot be elected unless some less worthy candidates are included.

(b) Purpose.—The end which the voter should have in mind is the good of the public, and hence it is not right to vote for candidates solely or chiefly because they are personal friends, members of one's own race, organization or religion, or because one wishes to gain favor or escape enmity.

(c) Circuмstances.—The voter must avoid all that is contrary to natural law (e.g., selling of votes, repeating, stuffing ballot boxes) or positive law (e.g., state laws require not only citizenship and a period of previous residence, but also other conditions such as registration and freedom from bribery and other election crimes). The opinion that politics is necessarily corrupt, and that all is fair that helps to win, is a false and pernicious doctrine. The conditions for ecclesiastical elections are given in Canons 160 sqq.

Fr. Titus Cranny, S.A. (1921-1981), The Moral Obligation of Voting:

4. CONDITIONS UNDER WHICH ONE MAY VOTE FOR UNWORTHY CANDIDATES

By the term “unworthy candidates” we do not necessarily mean men whose private lives are morally reprehensible, but those who, if elected, would cause grave injury to the state or to religion, as for example, men of vacillating temperament who fear to make decisions.

In practical life it is often difficult to determine whether a particular candidate is worthy or unworthy because there seems little upon which to judge accurately, especially in local or municipal elections. It does not follow that every Catholic is necessarily the best man for office and that every non-Catholic is not; nor that every Catholic will promote the interests of the common good of the state and of religion and that the non-Catholic will not. Even if a man is of sterling character in his private life, he will not by necessity prove competent in public office. Sometimes too, as St. Robert Bellarmine pointed out in his De laicis [c. 4, p. 7] the so-called evil rulers may do more good than harm, as Saul and Solomon. It is better for the state to have an evil ruler than no ruler at all, for where there is no ruler the state cannot long endure, as the wise Solomon observed: “Where there is no governor the people will fail” [Prov. 11:14].

When unworthy candidates are running for office, ordinarily a citizen does not have the obligation of voting for them. Indeed he would not be permitted to vote for them if there were any reasonable way of electing a worthy man, either by organizing another party, by using the “write in” method, or by any other lawful means. On the other hand, it would be licit to vote for an unworthy man if the choice were only between or among unworthy candidates; and it might even be necessary to vote for such an unworthy candidate (if the voting were limited to such personalities) and even for one who would render harm to the Church, provided the election were only a choice from among unworthy men and the voting for the less unworthy would prevent the election of another more unworthy.

Since the act of voting is good, it is lawful to vote for an unworthy candidate provided there is a proportionate cause for the evil done and the good lost. This consideration looks simply to the act of voting in itself and does not consider other factors such as scandal, encouragement of unworthy men, and a bad influence upon other voters. Obviously, if any or all of these other factors are present, the excusing cause for voting for an unworthy candidate would have to be proportionately graver [“Nearly all modern theologians admit that to elect a man whom one considers evil is not an intrinsically evil thing, and therefore it may sometimes per accidens be permitted in order to avert greater evils.” Prümmer, Manuale theologiæ moralis, 2, 604].

Lehmkuhl says that it is never allowed to vote absolutely for a man of evil principles, but hypothetice it may be allowed if the election is between men of evil principles. Then one should vote for him who is less evil (1) if he makes known the reason for his choice; (2) if the election is necessary to exclude a worse candidate [Compendium, 343]. The same author in his Casus conscientiae lists the general argument, adding that there must be no approbation of the unworthy man or of his programme [1, 729].

Tanquerey declares that if the vote is between a socialist and another liberal, the citizen may vote for the less evil, but he should publicly declare why he is voting this way, to avoid any scandalum pusillorum [i.e. to avoid scandalizing those weaker in Faith] [Synposis theologiae moralis et pastoralis, 3, 981]. Prümmer says the same [Manuale theologiæ moralis, 2, 604]. Actually, however, in the United States and in other countries where the balloting is secret, there seems to be no need of declaring one’s manner of voting.

Several authors including Ubach, Merkelbach, Iorio, Piscetta-Gennaro, and Sabetti-Barrett allow for material cooperation in the election of an unworthy candidate when there are two unworthy men running for office. Ubach adds this point: (1) There must be no cooperation in the evil which the man brings upon society after assuming office; (2) The voting must not be taken as an approval of the candidate or of his unworthiness. Merkelbach asserts that such cooperation may be licit per accidens if there is no hope that good men will be elected without voting for the bad ones in the same election.

As a practical point it may be remarked that at times a citizen may have to vote for an unworthy man in order to vote for a worthy one, e.g., when people have to vote a straight party ticket, at least in a primary election when the “split ticket” is not permitted. However the good to be gained would have to outweigh the evil to be avoided, or at least be equal to it.

In his Casus Genicot [Casus conscientiæ, 138], sets up a case of an election between a liberal and a Communist. To avoid scandal the citizen should give reasons for voting for the liberal. One does not support the evil candidate but simply applies the principle of double effect. This author also says that a person may use a mental reservation in promising to vote for an unworthy man.

Cardinal Amette, Archbishop of Paris, implies the liceity of voting for an unworthy candidate when he writes of voting for a less worthy one. “It would be lawful to cast them,” he writes,” for candidates who though not giving complete satisfaction to all our legitimate demands, would lead us to expect from them a line of conduct useful to the country, rather than to keep your votes for those whose program would indeed be more perfect, but whose almost certain defeat might open the door to the enemies of religious [sic] and of the social order” [John A. Ryan and Francis Boland, Catholic Principles of Politics, 207-208].

Thus we may say that it is permitted to vote for unworthy candidates (that is, give material cooperation) if these are the only type of men on the ballot lists; in order to exclude the more unworthy; in order to secure the election of one who is somewhat unworthy instead of voting for a good man whose defeat is certain; and when the list is mixed containing both worthy and unworthy men, so that a citizen can vote for the former only by voting for the latter at the same time.

🎩 tip: "The Morality of Voting: Is it Permissible to Vote for the Lesser of two Evils?"

Modernism.

How?

Alright, let's talk about "serious damage." Serious damage will occur (and has occurred) under both candidates. The vague promise of maybe somewhat curtailing abortion is supposed to elevate Trump's serious damage over Biden's. Not all politics are corrupt, but ours certainly is. 

Why bother quoting Novus Ordo moral theologians? Let me hear again how hypothetically "it may be allowed if the election is between men of evil principles." How much you want to bet he believed in the Triumph of the Immaculate Heart? I'm sure he would have seen the fake fall of the Soviet Union as the "peace" granted to the world by JPII's consecration and collaboration with Solidarnosc secret police informer Walesa. We must go along with the barely licit and permitted if we are going to survive!

Or look at this situation for what it really is. If you really believe Trump could or would repeal abortion, that's up to you. I think there's ample evidence that he's a perverted liar and a hardcore lifelong liberal with no intention of doing any such thing. That old chestnut has been roasted long enough. When juxtaposed next to the insane LGBT agenda, it's a big fat joke. All I see are ashes. I pray for the removal and/or destruction of all God's enemies.

But please, if you're going to talk about voting Trump, make sure that you also mention the sick reality of the rest of his platform. He needs to be corrected especially by those voting for him. 

I pray for the removal and/or destruction of all God's enemies.

Rebellion is not God's way. Conversion is.