If every country had a shield that kept all people in and all people out. Who would live?

most countries could .. the problem is the system is, and is being, set up to make everything interdependent and thats how control is maintained and broadened ... the idea is ancient and started eons ago with the first large cities being born with the introduction of money as a medium of exchange .. it allowed situations to be created where people relied on money and imported goods to survive which made those that controlled that kind of system the 'real' power .. thats how it is pretty much world-wide now .. most countries would have to completely change their system and society structure to become self sustainable, but it is definitely possible in most cases .. just not without radical, and probably bloody changes ..

Almost all countries that are large enough would survive because human beings are very determined and resourceful. Non Muslim countries would flourish, especillay ones with a lot of resident Jews but Islamic countries would degenerate even more than they already have.

The only country that needs a dome is Mexico. To keep them in.

Most countries could survive, but the government would be corrupt because there is no one to stop the corrupt government. Millions of people would probably be dieing because of this.

You sound like that X Gov, of Arizona. Not Mc cann. the other one.