Yes, although there is no strong or even logical connection between "faithful preaching" and "right political decision making," simply because of how complicated the political sphere is. To assume our congregants will decide well is to think too highly of our own preaching, their intelligence, and the translucence of local, state, federal issues, etc. So will the Bible alone, preached without reference to in-the-air events, guide us to right political decision making? No (like saying it will make us competent at science, or economics, or issues of medicine)--God will use his Word to graciously, supernaturally renew us, sanctify us, bring us to him, etc; we will become better disciples, and perhaps as better disciples, more mature disciples, we come to make more mature political decisions--and yet, there is a great variety of ways to proceed in political sphere, in matters of voting, such that 5 seemingly contrary policies might all find support by 5 mature believers. Therefore, it is erroneous to believe that merely preaching the Bible will produce the outcome the pastor would like and himself thinks is Biblical, even obviously Biblical. This is the height of arrogance, and admits of, in psychological terms, the false consensus effect, which is an egocentric bias common to us all.
I think the better reason to not announce guidance, if one is going to argue in that vein, practical guidance, about persons or policies or institutions, is simply that it presumes the one saying such things knows quite a bit. But frankly, our pastors are not experts in public policy; in constitutional law; in electioneering; et caetera.