[MaxPengwing]

No, it has already increased, but not due to Sweden and Finland joining. the increase was a direct response to Russia invading Ukraine.

https://www.uso.org/stories/3518-one-year-later-how-the-uso-...

https://www.nato.int/cps/en/natohq/topics_136388.htm

https://commonslibrary.parliament.uk/research-briefings/cbp-...

But in same time European allies has also increased their NATO soldiers.

[ttymck]

Yes, I am asking: all else equal, would more NATO members reduce the number of US soldiers deployed.

[Paradigma11]

There is no all else equal here. If your new member is the Democratic Republic of Congo the number would go up considerably. With Sweden/Finland it might very well go down since the border is far more defensible. But the US has a global footprint and those troops in Europe are nearer to potential conflicts in the middle east and northern Afrika, so it might make logistical sense to park them there anyway.