The belief that the Constitution is a perfect and totally infallible document. Also the belief that the Constitution allows everyone to do almost anything they like as long as it doesn't "hurt" anyone else, at least as long it doesn't seem to hurt anyone else in libs' eyes. Also, they take their interpretation of the Constitution to be the only possible interpretation, when in fact there are many different interpretations of the Constitution. Why do you think Supreme Court judges differ on what they think the Constitution means?
Constipational people don't want to listen to rational arguments or different interpretations of the Constitution. A constipational person will argue for abortion rights and same-sex marriage and use the Constitution to try to prove their point.