In other words, our constitution was designed by people who were idealistic but not ideological. There's a big difference. You can have a philosophy that tends to be liberal or conservative but still be open to evidence, experience, and argument. That enables people with honest differences to find practical, principled compromise. On the other hand, fervent insistence on an ideology makes evidence, experience, and arguments irrelevant: If you possess the absolute truth, those who disagree are by definition wrong, and evidence of success or failure is irrelevant. There is nothing to learn from the experience of other countries. Respectful arguments are a waste of time. Compromise is weakness. And if your policies fail, you don't abandon them; instead, you double down, asserting that they would have worked if only they had been carried to their logical extreme.

Try to look at causes and solve problems. Do not concentrate on military solutions. Do not seek military solutions. Terrorism is a political problem. Seek political solutions. Diplomacy works.

...never [enter] into dispute or argument with another. I never saw an instance of one of two disputants convincing the other by argument. I have seen many, on their getting warm, becoming rude, & shooting one another. ... When I hear another express an opinion which is not mine, I say to myself, he has a right to his opinion, as I to mine; why should I question it? His error does me no injury, and shall I become a Don Quixote, to bring all men by force of argument to one opinion? ... There are two classes of disputants most frequently to be met with among us. The first is of young students, just entered the threshold of science, with a first view of its outlines, not yet filled up with the details & modifications which a further progress would bring to their knoledge. The other consists of the ill-tempered & rude men in society, who have taken up a passion for politics. ... Consider yourself, when with them, as among the patients of Bedlam, needing medical more than moral counsel. Be a listener only, keep within yourself, and endeavor to establish with yourself the habit of silence, especially on politics. In the fevered state of our country, no good can ever result from any attempt to set one of these fiery zealots to rights, either in fact or principle. They are determined as to the facts they will believe, and the opinions on which they will act. Get by them, therefore, as you would by an angry bull; it is not for a man of sense to dispute the road with such an animal.

Another grave fault in our election system is that the campaigns are unduly strung out. [Election Administration in the United States, 1934, page 72]

As for the politicians, like everyone else in America, they were motivated by money, not ideals.

Indeed, it's not a stretch to say that most voters no longer choose their representatives; instead, representatives choose their voters.