Originally Posted by
Often1
Horrible advice and OP has it wrong. The reason he can enter Canada on an expired Canadian passport is that he doesn't need a passport at all. That's true of most countries.
It can take longer, cause you to get flagged for secondary inspection forever more and a whole parade of horribles. But, you won't ultimately be denied entry (in most places).
Exactly. Normal states cannot legally prevent their own citizens from entering. A passport is, literally, for passing foreign ports. It is a guarantee from your home country to other countries that you are a citizen.