Despegue : Roaster280 has it exactly right.That is how it was explained to us 2 weeks ago by an official the State Department. So all of us affected have appointments at the US embassy to get 10 years visas.
how exactly will the US find out that I ever did a layover in Khartoum
Ever heard of PNR and biometric passports scanning? you may have 10 passports, your biometrics are one. Everytime your passport is scanned on your way to or from a destination, the data goes into a central database. Welcome to the XXIst century.