In the Sermon on the Mount, Jesus instructs us to pray for and make the implementation of his Kingdom our number one daily priority, but (sadly) most churches either ignore these marching orders, or worse yet, encourage parishioners to actually participate in the politics of satan's fiefdom nation-states...😢
Discussion
Yes, many Christians seem to believe that Satan is currently the king of this world, I think based primarily on the fact that he attempted to tempt Jesus by offering him the kingdoms of the world, and Jesus didn’t dispute that they were Satan’s to give. It certainly seems as though there are evil powers and principalities in firm control now, with small pockets of resistance.
I’m not sure what your eschatological beliefs are but, as a futurist, I think we are heading toward a great tribulation, which Jesus will eventually squash at His coming.