We believe the Scripture teaches that we are to submit to government even if that government does not function entirely (or even primarily) by biblical principles (Romans 13:1-7). That principle is explicit in Peter's message to servants (1 Peter 2:18-19), which directly follows his more general comments regarding government (1 Peter 2:13-17). And that epistle teaches the same thing over and over again in varied ways: Submit even if you suffer, because in doing so you identify with Christ and are blessed (cf. 1 Peter 2:21-24; 3:1-2; 4:12-14; 5:9-10). There are times when we must obey God rather than men, but we believe that we should disobey the authorities only if they command us to do something directly against God's law (e.g. Acts 5:29 and its surrounding context).
That is a fine distinction, but it is precisely where the issue lies. If we say that Christians are only required to obey their government when it is functioning by scriptural principles, we then nullify the teaching of Romans 13:1-7 and 1 Peter 2:13-17 in just about any age of history-especially the time during which those passages were written! The Roman government was as corrupt and godless as any in history, and yet Paul and Peter told Christians to "live in subjection," "submit to every ordinance," and "honor the king."
So we believe that civil disobedience is justified only when government compels us to sin, or when there is no legal recourse for fighting injustice. The reason we draw the line there is simply because all the scriptural examples of civil disobedience fall squarely into those two situations. Any other kind of activism has no precedent in the Word of God and violates the spirit of Romans 13 and 1 Peter 2.