Historical Russia (no, not the Soviet Union) does have legitimate interests beyond it's current borders. For us to deny that, or worse to attempt to deny them to Russia, does risk existential war.
For what? So that Estonia can be in the German sphere of influence? Georgia too?
Ultimately the Russians are rational...or none of us would be here today. The balloon would have gone up in the 60's or 70's.
Must we have the Western World inhabit all of the Eastern world too?
If anyone contends we must, I ask...WHY?
And if it's "Freedom and Democracy"...why not the Central African Republic?
If the Russians are rational (your words) then stopping them now, while it is relatively easy, will not lead to “existential war”.
However, the Russians consider everything they do, geopolitically, to be “defensive”, regardless of whether anyone else sees it that way or not. Gingrich is correct in pointing this out. Putin’s own words about centuries of “containment” are the key.
Now, the difference between C.A.R. and Ukraine or Estonia is that we have (well, HAD, since we evidently are “without honor”) a very serious security agreement with Ukraine, not to mention that the majority of the people there understand and quite sincerely want to be a Western style democracy. Estonia is even more serious a security commitment (NATO ally) and is a rather well functioning “Western” democracy and economy in fact. C.A.R. is the opposite, with even its
Prime Minister Nicolas Tiangaye saying it is a “non-state”.
The ramifications of the US abandoning these commitments is devastating: It not only encourages aggressions now and in the future, but even worse, unless a Russia / China axis becomes totally dominant, quickly, it almost guarantees at least a mid-scale nuclear war down the line.