Airmail Service - What will the USPS mail man do, if a package was delivered to the correct address but no one recieved it?

What will the USPS mail man do, if a package was delivered to the correct address but no one recieved it?

What will the USPS (United States Postal Service) mail man do, if a package was delivered to the correct address but no one recieved it? The package is PRIORITY. The mail man, hits the target and is right infront of the door of the recipient but no opens the door for him after he knocks. What will the mail man do? Will he leave the package on the recipient's door step and leave? Or will he return-it-to-sender?

Public Comments

He should leave it at the door. Unless the sender requested a signature.
Priority Post, s/he should leave a "notice of attempted delivery" telling you where the parcel can be picked up and at what time it will be available. This happens regularly at my house but we are served by the Royal Snail (Canada Post) not the Bald Snail (USPS).
Normally they will leave it on the porch near your door. Unless the package comes with special instructions not too.
The mail carrier will leave it, unless it has to be signed for, or if there is no safe place to leave it.