The US president doesn't have that power and that's a good thing.Will China Joe Biden impose a mask mandate??
He could try to explain why people should wear masks and get experts involved (not politicians).
As a leader is easy to force people do do things, make things mandatory.
It's harder to educate people and to let them decide by themselves.
So far every US politician has made a poor job of not bringing politics into what should only be a public health debate.
One side will tell you masks don't work and that could even kill you.
It's not true.
One one side will tell you masks are magic and work 100% of the time.
It's not true either.
People just need to be nice with eachother, not attack people because they decided to wear a mask, or not not wear one.
But hey that's obviously asking too much.