That's the whole problem, if Russia can create a situation that would cause member states to doubt their support if the defense clause is enacted the whole NATO and EU enterprise could be shattered. Most Americans don't even know Estonia exists much less that it's an ally we'd need to defend, a muppet like Trump would have wide support for withdrawing to the continental US and leaving Europe to defend itself. France and Germany are no where near prepared for squaring off with Russia or its proxies not politically or militarily.
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