This approach begins with a simple and undeniable premise: that there is no way that anyone is going to convince everyone else to accept one unified belief system. Liberals will never convert the conservatives, and the conservatives will never convert the liberals. We’re never going to all agree on the wedge issues, and it’s not even realistic to expect that people will learn to discuss these topics in a calm, rational manner any time soon.
Therefore the only way that we can hope to unify in the face of a common threat is to bring it down to the lowest common denominator. What can we use as our unifying principle? What is our common ground?