|Wingnuts: they're everywhere!|
Republican presidential contenders may be feeling nostalgic for the days when a candidate could focus on just one pledge: the oath of office.And so they take this oath and that oath -- all crazy, of course. But that's not the point of this post. The reason why rightwingers and religious loons are so authoritarian is that their brains can't update. They cannot take in new information. This is the crucial difference between liberals and rightwingers: our minds can update.
If science reveals something, liberals incorporate the new information into their worldview and act accordingly. Liberals pay attention to the world around them. Authoritarians, on the other hand, rely only on preconceived notions. That's why they like things like the ten commandments and bibles and old hairstyles. They love rules. And they get absolutely crazed when anyone suggests new information that might affect these rules. Heresy!
So it makes perfect sense that people of this stripe think it a good idea to take ideological pledges. They don't need to see the actual situations that these pledges will apply to -- because there's no reality in their equations, only rules. So they take a pledge and, come hell or high water (or, you know, facts), they will not change their stance.
This happens because their brains aren't working properly. Being rational requires that we take the real world into account. They don't. They take pledges.