The Bible specifically tells us that circumcision is no longer necessary. One of the Apostles referred to it as the "yoke our fathers were not able to bear", and declined to compel the Gentile converts to circumcision. Do you doubt the Apostolic word?
Exactly! Those who claim the Bible tells us to circumcise are often casual Bible thumpers who get their Gospel from Readers Digest. As far as libs vs. conservatives, well I don't know if there is one pushing it or not, but I do know that circumcision is done more often here by the big Mega Churches who usually support gay marriage and abortion, and is waning off fast in our own Catholic church here in Chicagoland. Hers a Bible quote for you keeping score:
Galatians 5
Freedom in Christ
1It is for freedom that Christ has set us free. Stand firm, then, and do not let yourselves be burdened again by a yoke of slavery.
2Mark my words! I, Paul, tell you that if you let yourselves be circumcised, Christ will be of no value to you at all. 3Again I declare to every man who lets himself be circumcised that he is obligated to obey the whole law. 4You who are trying to be justified by law have been alienated from Christ; you have fallen away from grace. 5But by faith we eagerly await through the Spirit the righteousness for which we hope. 6For in Christ Jesus neither circumcision nor uncircumcision has any value. The only thing that counts is faith expressing itself through love.
7You were running a good race. Who cut in on you and kept you from obeying the truth? 8That kind of persuasion does not come from the one who calls you. 9"A little yeast works through the whole batch of dough." 10I am confident in the Lord that you will take no other view. The one who is throwing you into confusion will pay the penalty, whoever he may be. 11Brothers, if I am still preaching circumcision, why am I still being persecuted? In that case the offense of the cross has been abolished. 12As for those agitators, I wish they would go the whole way and emasculate themselves!
Source:
http://www.biblegateway.com/passage/?book_id=55&chapter=5&version=31