A common misconception, that. .com is not a country-code TLD. It was never intended for use by one country; it's explicitly a generic top-level domain, for use by international organisations.

What gives the US "jurisdiction" is that it's nominally controlled by VeriSign and thence ICANN, which is a US quango, so owners of .com domains are in a legal relationship with a US entity. Outside the US, people have been known to get quite worked up about this arrangement, and there have been serious suggestions that ICANN should cede control (or transfer directly) to a UN body. Whether interference as in this case is legal in international law is, as far as I know, untested.

The TLD which was originally intended for use by US commercial organisations was .co.us, which nobody seems to bother with.

Nope, .co.us was (and is) intended for Colorado. There never has been a second-level domain under .us specifically for commercial organizations.

Whoops, good catch.