There are a lot of great causes that I think are important. Be they social causes, political movements, efforts for promotion of ideas, many people are involved in many things that give value to our culture and world. Some of them are things that, in another life, I would be willing to step into and personally assign my name to, either in support or in opposition.
But I won't do it. Not now, and not as long as the Lord has called me to serve Him in pastoral ministry.
A Pastor is, by profession and function, something of a "face" for the church, especially his local congregation. In some cases this is taken way too far-- and in almost every case, it is something that Pastors must be diligent to keep in check. They are not the church, or even in charge of the church, but they are the most prominent leaders in the church. And in many people's minds, they are the face that people think of when they think about the church. This is even more true outside of the church than it is inside it.
Thus, as a Pastor I must not be an activist. Why? Because an activist puts a priority on something other than the centrality of the Gospel and the faithful teaching of Scripture.
This isn't always bad-- there are times when an issue needs to be the front-and-center concern, and the Gospel's relationship to it must be secondary in that discussion. There are issues of political or social change that the Scripture doesn't directly speak to, and those who try to make the discussion all about the Scriptural principle that indirectly relates only serve to muddy the waters.
(Let me make this disclaimer: I'm not saying that Scripture is insufficient to give guidance for godly thinking and living in all spheres of life; Scripture IS sufficient for that. But Scripture isn't exhaustive in offering prescriptive conceptual thinking about all issues that face us today, and it is irresponsible to assert that it does.)
Some examples: while Scripture offers help in understanding the concept of just war, it doesn't directly speak to whether a particular war or military action is just. Scripture does discuss the stewardship of our world and environment, but it doesn't offer direct teaching about global warming. And although Scripture speaks to how a believer ought to behave in relation to his governmental officials, it doesn't address whether we should be in favor of states' rights over federalism.
And here's where the divide comes for me, as a Pastor: if my charge is to proclaim the truth of Scripture in season and out of season; if I am to preach, not myself, but Christ as Lord and myself as a servant; if I am to know nothing before my flock except Christ and Him crucified-- if these are what I am to be about, then I MUST not be an activist. To take an activist position would be to turn my focus away from this charge.
If the church is charged with demonstrating the historical marks of the church-- Word, Sacrament, and discipline-- and only that, then a church must not assume a particular position on an activist cause. And I, as the Pastor and "face" of the church, must not do so either.
Scripture DOES teach a lot about how we might think about social and political issues, and over the course of my ministry (and even over the course of the next year or so) I will address these as they present themselves in Scripture. But I must stop short of waging judgment on particular political leaders, individual social causes, or specific political or social issues (and whether I agree or disagree with them).
I have opinions on them, and I'll even share some of my observations at times. If I'm doing my job well, however, you'll walk away without certainty about what my exact political and social positions are. That is as it should be-- because I am not an activist, I am a Pastor.