In a sense, we're already along way down that slope. That's what happens when, year after year, scoundrels are elected to office. And they, then, appoint other scoundrels.
There is no system, no Constitution, no tradition that can "save" people from selecting bad leaders. Regardless of how beautifully constructed our Constitution and system are (were), if the people elect criminals as leaders, and if they do it long enough and widely enough, there is nothing that can stop that system from degrading -- not even a Supreme Court.
The only answer is to elect honest, upright people who do not believe in winning at every cost. If that cannot be done, then there is nothing that will save the system.
The Democrats are willing to destroy the system for power. If the people elect them, then they will have the power to do just that. And there's nothing on earth that will stop it.
Unlike what the Buchananites and the Libertarians think, if you lose elections there is no victory "down the road", there is no moral victory. There is only the end of the system.
To preserve the country that we have known, the only answer is to win the elections.