Section — Wouters, Manual of Moral Theology
Section VIII. On the Duties of Electors and Deputies
I. Electors are bound to use the right of electing as follows:
The obligation of electing is grave: 1. if there is hope through one's own election of bringing it about that there will be present a number of good deputies sufficient for establishing good laws or at least for warding off harmful ones; in other words, at least in practice, that there will be present a number of good deputies greater than, or at least as great as, the number of wicked deputies; 2. if there is hope through one's own election of warding off a deputy who by his influence will notably harm the common good; 3. if it is of great importance that it be signified how many electors favor right principles, for example if from the number of votes the boldness of adversaries will be diminished.
Outside the aforesaid cases the obligation of electing is everywhere light, either because there is hope of increasing the number of good deputies, or because at least it is of interest that it be signified how many men oppose wicked principles. A just cause excuses from a light obligation. I said everywhere; for:
If neither of the enumerated causes is present, there is no obligation of using one's right, unless perhaps from a law which obliges at most under light sin, and which is satisfied by a blank ballot dropped into the urn. If the election is only between two wicked candidates, and the worse will certainly be warded off without the cooperation of Catholics, per se one should abstain from the election.
Corollary I. He who elects an unworthy deputy:
a) Sins gravely: 1. if he is led by a wicked end, for example because he approves wicked principles; 2. if it is to be feared that by electing an unworthy one he brings it about that the number of good deputies sufficient for establishing good laws, or at least for warding off wicked laws, will be lacking; 3. if it is to be feared that by electing he is the cause why a deputy is elected who by his influence will notably harm the common good.
b) Does not sin if he acts thus so that a greater evil may be forestalled, for example so that a worse candidate may be warded off.
c) Outside the aforesaid cases, he sins at least lightly.
Corollary II. He who abstains from an election is not bound to restitution of the damages that followed, because he is not bound by commutative justice to use the right of electing. There is a dispute about one who has voted illicitly; but the obligation of making restitution is denied with sufficient probability, because electors are rather the occasion than the cause of the damage, nor is it sufficiently proved that there belongs to the community a strict right that an unworthy candidate not be elected.
II. Deputies are bound to promote the common good, especially by establishing good laws and warding off harmful ones. Moreover, they sin gravely: 1. whenever they vote for a law intrinsically evil; 2. when, either by abstaining or by voting, they are the cause why a gravely harmful law, even though not intrinsically evil, is established, unless this is done so that a more harmful law may be warded off.
Corollary I. Deputies who, either by abstaining from voting or by giving a vote, have been the cause why a harmful law was established, are bound to restitution, because by reason of their office, to which remuneration is joined, and therefore from commutative justice, they must, if they can, promote the common good and ward off evil.
Corollary II. The things said about electors and deputies have greatest force concerning electors of legislative assemblies and concerning deputies to the aforesaid assemblies; nevertheless they can also be applied to electors of administrative assemblies, for example of a province or municipality, and to deputies to the said assemblies.