Here is part of RC Sproul, Jr.'s answer to this question:
Should American pastors ever preach warning us of our burgeoning police state and the erosion of our liberties?
The answer to the question- what should pastors preach, is simple enough. They should preach the Bible. The Bible, according to the Bible, equips us for every good work. There is nothing of importance, and surely all would agree that liberty is important, that the Bible does not speak to. Where it speaks so ought the preacher to speak. We don’t come to the Bible, or any of its texts, hoping it will support our own message. Rather we come hoping we will communicate its message.
The more difficult question is one of priorities. The question is not if we should preach against the grasping state, but how often ought we to do so? And that, I would argue, is answered not by knowing the Bible, but by knowing ones congregation. Too often we tickle the ears of the flock not by speaking well of them, but by thundering against the sins of their enemies. A steady diet of “We are the oppressed minority who are being overrun by the state that hates us” may increase our blood pressure, but isn’t likely to increase our holiness.