I don`t have any idea the theology of the church you attend but if this is an issue of more pressing concern than salvation through Jesus it may be time to find another place of worship.
I think the key in dealing with problems like this if realizing where the church stands on the inerrancy of Scripture. Usually those denominations or branches of denominations which do not hold to the inspiration of Scripture by the Holy Spirit, are the ones who then theink it is okay to interpret things they way they want, rather than the intent of the Author. A greater issue than your pastor souting off without facts on a politiacl issue, is that it might be indicative of how he handles other issues. Spiritual matters are too important to allow to rest on some preacher's opinion.
The inerrancy of Scripture just mans that the Holy Spirit inspired the original authors, and that God got written what He wanted written. The copies we have today are very good, and the studying of the texts shows they are the best attested documents in history.
What this means is, if it really was God Who was speaking, and if we really have what God wants us to know, there is an accountability. He says lying is wrong, so spouting an opinion on politics which is not based on fact, would be a sin to Him. If the pastor twists other areas of Scripture to allow for homosexuality, for abortion, etc., God is not pleased.
Discernment on alot of issues comes from one's understanding of inerrancy. Where do we get truth?