And political success and the ultimate success of ideas or ideals have little to do with each other (see Vaclav Havel or Lech Walesa). Truth is an unstoppable force. The Senate is a barely moving body. I'll take the former (truth) over the latter (political success) any day. If we are in politics for politics sake, we are playing parlor games. If we are in politics for the sake of forming a more excellent nation, then truth means everything. Otherwise, it's just who has the best propaganda.
Politics is the art of the possible. The purpose of political action tend to lie outside of politics, but ignorance of the way things work is no way to accomplish your purposes.