Yeah. The moment American soldiers step foot across the Canadian border what are we going to do? It would already be over. We have no defense against the largest military in the world, and we stand no chance of defending the longest continuous border in the world. We will only be able to fight as an occupied resistance.
I'm sure they want to mean it. But the reality is that when Russia starts making moves they will be pre-occupied and likely won't be able to help much across the Atlantic
Even if Russia didn't do anything, how the hell is Germany even going to cross the Atlantik without getting blasted into oblivion? If they actually wanted to attack the US they'd have to start with the tens of thousands of US soldiers and secret service agents on their own soil.
The only European countries with nukes are the UK and France (225 and 290, respectively). As of January 2024 the world has ~12,121 nukes. America has 5,044 of them