When they don’t argue on behalf on democrats or republicans (and they have done both) but relentlessly refuse to compromise the Gospel of Life in ALL aspects.
They must make clear that torture can never be supported, our wars fail Just War Theory because they are not properly declared by Congress (and are thus illegal), that citizens have a natural right to privacy and should not be spied on by the government without just cause (how radical!), and the other pro-life issues we are all well versed in (save marriage, in which government should get out of it altogether).
Make it clear, no more lesser of two evils. The parties will come to us, they will not receive our votes.