I have a question for your teacher:
What defines a liberal, a conservative, or other faction? How would I recognize one of these people?
Because right now the terms liberal and conservative, in particular, have been distorted to such a point that they have become meaningless labels that are merely used as a pejorative to dismiss someone else's ideas. I have lots of conservative friends. They aren't nazis. They don't hate gays. They really don't even care that much if you say Merry Christmas to them. They do care about things such as personal responsibility. I have a lot of liberal friends. They don't want Sharia law. I have never met one who thinks that abortion is a good thing. They don't want to give their money and yours to undeserving people. They do care about such things as people getting a fair chance.
By separating people into these stereotype groups, your teacher is helping to ingrain the stereotype.
The answer that is probably being sought is liberals. But do you also not think that those currently in power in the U.S. (who would normally be identified as conservatives) are not using the powers of government to promote what they see as social progress? Simply put, whoever controls the governmental power is going to use it to further their agenda - and they will call it social progress.