“Covenants, without the Sword, are but Words, and of no strength to secure a man at all.” Thomas Hobbes
International peace treaties are like many other things liberals cherish; they are beautiful in theory, useless in practice, and a dangerous trap to anyone who puts faith in them. An accurate knowledge of the history of treaties would undermine the belief in them that leftist professors are trying to promote, so college profs (and the textbooks they write) tend not to cover the subject very well.
The leftist culture of most college history faculties requires professors to cover up a lot of politically embarrassing data, and the history of international peace treaties is just one example of that. Positive examples of the results of peace treaties are hard to come by, and negative ones abound, so professors who want to indoctrinate their students are forced to suppress a lot of actual history while claiming to teach history.