A reader makes a salient point:
There is a very simple point, central to your argument about doubt, that escapes Mr. Goldberg. Even if people are certain something is right or wrong or good or bad, people can be humble about their ability to achieve that vision. The utopian impulse is the result not only of delusions of omniscience but also delusions of omnipotence.
One might be sure illegal immigration is harmful but unsure about how to solve the problem in a way that doesn't involve incredibly high costs - costs one is unwilling to pay. One might be certain Saddam is evil but still question our abilities to affect positive change in the Middle East and Iraq. Bush is not only sure that torture isn't irreparably harmful to liberal values; he is sure that he can use torture effectively.
Omniscience plus omnipotence: the conservative nightmare, but today's Republicans' dream.