here's an example of the credibility index in action. actually on liberty-type grounds i oppose the individual mandate in obama's health insurance bill. also i think it's unconsitutional. but if i assert that it is unconstitutional, given that i think it's wrong on other, more general grounds, you should suspect that i twisted the evidence on the constitutionality. not that i necessarily have, but i had a motivation to. now before you try to grapple with the arguments, you should regard someone who opposes the mandate but thinks it's probably constitutional as particularly credible; you should eyeball their constitutional interpretation as a sincere attempt to deal with the available info. likewise someone who supports the mandate with all the fervor of a great and generous soul, but who doesn't find any authority in the constitution to do it. now, are there any such people?