Notice the connection between all and one in this passage:
1 Tim. 2:1-7
First of all, then, I urge that supplications, prayers, intercessions, and thanksgivings be made for all people,  for kings and all who are in high positions, that we may lead a peaceful and quiet life, godly and dignified in every way.  This is good, and it is pleasing in the sight of God our Savior,  who desires all people to be saved and to come to the knowledge of the truth.  For there is one God, and there is one mediator between God and men, the man Christ Jesus,  who gave himself as a ransom for all…
Prayer in the church is not to be self-focused, but as large as the mission of God in the world. His concern is for all people (think nations, ethnicities, ages, political views, economic categories, moral standing, friend or foe, etc).
The all is tied to the one. For the Bible does nto speak of Gods who have localized areas of control, but one god over all people. God is one, and there is only one, THEREFORE his concern is for all.
Also the prayer for political leaders is not over so much who they are, but that the effect might be conducive for spiritual living and, in context, for the accomplishing of the mission of God. The pagan Roman empire created a peace (Pax Romana) and roads over which missionaries travelled with considerable freedom.