Professor Tamanaha’s Second Mistake?

As a follow-up to Patrick’s recent post, Professor Tamanaha appears to makes a second mistake. What if the believer and the unbeliever have very different moral justifications for their political decision on some specific issue, e.g., abolition of the death penalty, but they concur that capital punishment should be abolished. However there is a distinction that is to be kept in mind about their concurrence: the believer, in this case a Christian, relies on moral formation based on faith, but the non-believer cannot base personal moral choices on the inspiration of faith but on something else that relies exclusively on human resources.

I have read Professor Tamanaha’s thoughtful post, to which Rob refers, in its entirety, but it seems there is a limit to the claim Professor Tamanaha makes when he asserts the following:

However, if Christians make political decisions by the lights of Christian doctrine, and it turns out that there is no God or that Christianity is wrong about the nature of things (two distinct possibilities), then Christians will have inflicted their false religious beliefs on others, with immediate consequences.

What is the non-believer to do in this case in order to avoid the “immediate consequences” inflicted by “false religious beliefs”? Convert to a stance in favor of capital punishment? I don’t think this is what Professor Tamanaha has in mind, but it would appear that there is another limitation inherent in that portion of his argument, which I have reproduced above.    RJA sj