I’m unfamiliar with German basic law, but considering the lawlessness we’re seeing play out in the US right now, I’m curious how/why modern constitutions are less vulnerable?

By this I mean: it’s not as if the things we see playing out are lawful. Is there a structural difference that somehow prevents the same kind of lawlessness?

Put another way, what stops a movement that decides to ignore Germany’s constitution from ignoring it should they somehow gain power?

For starters, Germany does not give a single person the right to be king with decrees and military leadership.

Also (though not an issue with the law itself) it's really dangerous only having two parties at the helm.