with as close to the best system as we can realistically ask for
Actually, not very close at all to the best. Our particular system, the U.S. constitutional republic, was the first of its kind and is now over 200 years old. As with most technologies, more recent models have incorporated significant improvements over the original. Unfortunately, ours was deliberately constructed to be extremely difficult to upgrade. Many desirable modifications are not even a possibility, due to the original design specs. We are told this is a feature, not a bug.
If you are at all interested in politics, go read this very entertaining and thoughtful book:
The Frozen Constitution by Daniel Lazare.
Or as I like to think of it, "Why Nothing Ever Gets Fixed in the USA".
By the way, I don't think the people who are currently running the USA are conservatives by any reasonable definition of the word, unless perhaps you classify them as monarchists.