This is absolutely the point of sanctions, its the modern day equivalent of siege warfare. Using some arbitrary method, choke the flow of resources into a nation-state and then the economy takes care of the rest. The nation-state gives in to the demands if it is not strong enough. Anyone who attempts to get around the methods imposed is basically trying to break through the siege.

Yes. That is how sanctions work. And since US companies supply so much hi tech equipment and Financial instruments, banning a country from any trade with US companies is basically an indirect way of shutting them down.

They're called secondary sanctions.

https://www.exportcompliancematters.com/2016/07/25/secondary...

Yup. There are all kinds of entities you are not allowed to do busines with. In fact you usually need to know who the end-user is, etc.

However, this gets most important with ITAR and EAR which are items with military or "dual use" applications...

https://en.wikipedia.org/wiki/International_Traffic_in_Arms_... https://en.wikipedia.org/wiki/Export_Administration_Regulati...

Yes and for a good reason. A good, maybe extreme, example is of A.Q. Khan. It is suspected that US supported Pakistan with nuclear technology. Then Khan's company ERL helped Libya, North Korea, Iran and China develop their own nuclear weapons program.

https://en.wikipedia.org/wiki/Abdul_Qadeer_Khan#Proliferatio...

> does the US really try to enforce its export controls not just on our own country, but on foreign countries?

Yes. We run the international world order. Our sanctions are pretty much an international edict that all nations/companies have to adhere to. It's a perk of being the sole economic and military superpower and being the leader of the international world order since ww2.

> do we really expect to keep all our goods from making it there by way of third-parties?

Yes. Not only that, our national interests trump foreign countries'/companies' interests. We blocked a german company from selling itself to a chinese company.

http://www.scmp.com/news/china/economy/article/2051421/obama...