By virtue of supernatural faith in God, in Christ and in the Lord's promises to the Church, Catholic are obliged to follow the guidance of the Magisterium in matters of faith and morals. With the advent of modern democracies, a theology of Christian voting has steadily built up, first through the work of theologians–forming a common Catholic moral tradition, then, through positive teaching of the Magisterium. Not all issues have been addressed by the Magisterium, and in such cases common teaching should be relied upon as representing the consensus of the theological tradition. In these answers on voting, this moral theology tradition will be relied upon when the Magisterium has not specifically taught.
Two things should be noted about this statement, it concerns both politicians running for office and political programs. Indeed, political programs are mentioned first. A single politician cannot effect new laws, change existing laws, approve expenditures, manage the economy, provide for internal and external security, appoint members of the judiciary, or otherwise fulfill the myriad responsibilities of government. They necessarily join with other politicians to do so, most often with members of their own party, though ideally in a political consensus that reflects the common good. It is therefore morally insufficient to consider ONLY the politician, without considering the likely overall effect of voting for that individual, given their association with particular political programs and interest groups.