I tend to believe that God uses everyone on Earth to do His work. I also believe that God doesn't play favorites. The unbelievers cannot "hear" God. God could be getting their attention with a little robin chirping in the tree. To unbelievers, it's just a little robin chirping in the tree.
I think in sort of a roundabout way we are saying the same thing.
God was with Reagan and with Bush because they did heed His call and strived to do His will.
Good point about unbelievers not "hearing" God.
Somewhere in the New Testatment, letters from Paul I think, it is stated that all heads of state are in the position they are in as a result of God's plan and will, that would go for Bush, Putin, Chirac.
Whatever we do, whether truck driver, doctor , president, I believe if that is our calling, then that is what God has called us to do.