In particular, I think Daniel would have referred to the failure of the Constitution leading to the end of freedom throughout the world, not to anarchy. In a world still dominated by more or less absolute monarchies, anarchy wasn't the problem to be concerned about.
It’s entirely possible — indeed, probable — that the Jefferson quote is a compilation of thoughts he did put to paper over his long life. I’ve spent a lot of time in the UVa Jefferson papers site and those thoughts are — and that concern is — everywhere.
And the Webster quote doesn’t sound like him?
Then I suppose these also don’t sound like him:
“A strong conviction that something must be done is the parent of many bad measures.”
Daniel Webster
“God grants liberty only to those who love it and are always ready to guard and defend it.”
Daniel Webster
“I was born an American; I will live an American; I shall die an American.”
Daniel Webster
Both these men would fit right in here at FR.