"I exhort therefore, that, first of all, supplications, prayers, intercessions, and giving of thanks be made for all men; for kings, and for all that are in authority; that we may lead a quiet and peaceable life in all godliness and honesty. For this is good and acceptable in the sight of God our Saviour." (I Timothy 2:1-3)
These verses explain one of a Christian's responsibilities towards government. We are to pray for and give thanks for our leaders and those in authority over us. We need to pray that God will give them wisdom (see Proverbs 8:15-17) and guide their actions. It doesn't say we only pray for those leaders we like or agree with! Why pray for our leaders? So that we can live a peaceable and quiet life! Why pray for our leaders? It is good and acceptable in the sight of God.
Praying for our leaders is one responsibility Christian's have towards government.