I would also add that isn't empty talk like "Well he said it once, non biggie". That statement by POTUS itself drove the national policy other countries. When POTUS says "other nations you are with us or are our enemies", that matters.

That is a signal the reverberates around with "do we dare to anger USA on this one". The Afghan war partisipants list is long and contains some not so obvious participants often doing rather small token participations. Which I think is exactly "Well we have to show we are with USA".

For example here in Finland in the after action report of Finnish participation in Afghanistan tells the reason wasn't building peace, it wasn't even combat experience. It was "coalition and alliance building" aka showing USA "we are with them".

In the after action study one of the interviewed decision makers literally directly quoted:

Yhdysvallat sanoi 9/11 jälkeen: olette joko meidän kanssa tai meitä vastaan.”

United States said after 9/11: You are either with us or against us.

Right above explaining how it was 20 year long very unpopular operation caused losses and achieved nothing in Afghanistan, but hey the Finnish NATO application will go through with flying colors.

The whole time the media blitz was about "Helping and building peace in Afghanistan". When in reality we went in because USA publicly extorted pretty all of west to show colors.

This isn't only in Finland in other European after action reports have shown similar "We went in, because Bush publicly demanded show of loyalty".