I suggest

political debate would be more enlightening if we asked proponents to focus on their assumptions. When you say that your policy proposal would be an improvement, what are the key assumptions behind that statement?

For example, suppose that someone proposes that health insurance should be made mandatory. Below are a set of assumptions that might be consistent with such a policy. In parentheses, I give a score that indicates my degree of belief in the assumption. The scale goes from 1 to 5, where 5 means that I strongly accept the assumption, and 1 means that I am highly skeptical of the assumption.

–People who do not buy health insurance will nonetheless obtain medical treatment. (5)

–When the uninsured are treated, the cost of their care necessarily falls on someone else. (2)

Think of a proposal that you have on policy. Try to put together the chain of assumptions that support your proposal. Imagine having other people go through the same exercise with their proposals.