Originally Posted by
rubesl
You can always enter the U.S. with an expired passport, or no passport if you are a U.S. citizen. If you are a citizen you cannot be denied entry. BUT, getting an airline to agree to fly you (because they are subject to fines if you're denied entry) is another problem. Also, be prepared to spend more time at your entry point to verify your citizenship, especially if you're trying to enter with no passport.
Also should be noted, if you transfer in a 3rd country you may not be able to use this option.
By rule, if you were to get to US, be found inadmissible, you'd be returned to the country you just flew in from, not where you originated. Thus why some countries require you to be admissible to their country to transit.