"For he \[the ruler\] is God's servant to do you good. But if you do wrong, be afraid, for he does not bear the sword for nothing. He is God's servant, an agent of wrath to bring punishment on the wrongdoer."
Paul here states that God has given to the civil magistrate a weapon to enforce the laws. We call this the power of the sword. It means that rulers have the power under God to back up their decrees with the use of force. They may use that power rightly or wrongly, but the power itself is not something they have usurped. It is given to them by God. This power entails the power of capital punishment and the power to make war. Both of these powers have proven controversial in church history.
Consider war. All Christians are called to be "pacifists" in the sense that we are to love peace and pursue it. The use of the sword as a restraining device, though legitimate, is a means of last resort.
In Christian history three theories of war have been advocated. The first is the position of pure pacifism, which states that no Christian may ever take up arms. The second is the position summed up in the phrase, "My country, right or wrong." This position says that the Christian citizen has a duty to fight in whatever kind of war the government decides to prosecute.
Between these two extremes lies the "just war" position. The just war position has been advocated throughout history by the vast majority of Christian ethicists in all branches of the church. Based on the Bible, the just war position states that some wars are justified, and Christians may and often should bear arms in such circumstances, but that other wars are unjustified, and Christians must oppose such wars.
What determines the difference? Basically it is this: A just war is a defensive war. It is right and proper for the magistrate to call Christians to help defend its borders against aggressors. On the other hand, Christians should oppose wars of aggression, because they are nothing more than murder on a grand scale.
With regard to capital punishment, the Bible clearly authorizes (indeed commands) it in Genesis 9:6, which reads: "Whoever sheds the blood of man, by man shall his blood be shed." One purpose of punishment, including the death penalty, is retribution. According to Romans 3:3, the sword of the ruler is a terror to evildoers, so that deterrence is another value of punishment.
Coram Deo
Just war theory can get rather murky and difficult to apply, particularly when a nation is whipped up into an emotional fervor. Be certain that you reach your decisions based on careful, sober, biblical analysis and not on media hype or political party affiliation. Encourage your political leaders to do the same.
