Of the 196 answers in the Countries of the World quiz, only 39 can be formed using only letters of the alphabet that also appear in "THE UNITED STATES OF AMERICA".
Note: As long as a letter appears in "THE UNITED STATES OF AMERICA" it may occur any number of times in the country you enter. Only names as they appear in the "Countries of the World" quiz are accepted. If you enter a country containing a letter NOT in "THE UNITED STATES OF AMERICA", then the game will end and that country will appear with the "offending" letters capitalized. Sorry, there is no option in "Minefield" style games to display remaining answers.