What if it is not just Estonia? What happens if it is all the Baltics and Poland at the same time? We live in interesting times.
The Russians can take over the Baltics in 48 hours. It would’t be a close contest. We have nothing with which to stop them and the Cold War Tripwire is gone. And if Russia re-annexed those countries, we wouldn’t instigate World War III over it.
NATO guarantees are so much p*ss*ng in the wind and we know it and Moscow knows it. At the moment the Kremlin doesn’t want to bite off more than it chew.