Is a country's name a metonym - and when? E.g.: "The White House" / "Washington" / ..."The U.S.?"

I'm interested in figurative language and metonymy in particular. Sometimes it seems hard to tell if a term qualifies as a metonym or would be considered linguistically "literal." One case is when using the name of a country.

The White House opposed the plan...

Washington opposed the plan...

The U.S. opposed the plan...

The White House is commonly cited as a metonym for the U.S. executive branch government. It's the type of metonym "where one thing contains another." Washington is also used this way, using a broader structure to describe U.S. government entities.

If we go even wider in scope, we get to The U.S. Does "The U.S." qualify as a metonym in this context? It seems to function like one, but references to certain aspects of a country by using the country's name seem so common that it sounds odd to think of that as figurative language.

BONUS: If "The U.S." is a metonym in this case, where is the boundary for a country's name being figurative vs. literal? It seems like the only case where the country's name is inarguably literal is when referring to its geography. In other cases I can think of where a country's name is used, it appears to be a placeholder for some part of the country (its government, economy, agency, military, electorate, demographics, etc.). Is that true, or are there other rules or cases?

"A refugee lives in the US," -- literal.
"A refugee went to the US." -- literal.
"The US took in a refugee" -- metonym or literal?
"The US sent back a refugee" -- metonym?

All three of these phrases- The White House, Washington and The US- may be used to describe a small group of people instead of the whole, making them all metonyms.

Look at this definition from google:

a word, name, or expression used as a substitute for something else with which it is closely associated. For example, Washington is a metonym for the federal government of the US.

Check for one.

Now check this out from Wikipedia:

On the other hand, "The White House said" is metonymy, but not synecdoche, for the president and his staff, because, although the White House is associated with the president and his staff, the building is not a part of the people.

Check for two.

And this site, finally, describes the United States as a metonym (as many foreign countries' names are in international politics:

The United States will be delivering the new product to us very soon.

All three are confirmed to be metonyms, not only because of our conjectures that anything used as a substitute for another through close association is a metonym, but also because the Internet backed us up.

For your bonus question, they would also be considered metonyms, since the United States is not sending the refugee back nor taking him in; it would be representing the customs official or officials making that decision, and as a whole representing a part, both statements would be metonyms. Excellent point about geography; barring a few exceptions, it indeed would be the only time the U.S. is being used literally.

While common, these are definitely figurative uses since they all refer to the individuals making up the relevant branch of the US government or the electorate.

So, yes, these are all metonyms.