When does personal loyalty to a homeland transition into blind nationalism?

Is America a perfect country? Hell no it has it problems, but it could be a lot worst and here thing we, we as the people could debate about how America is so bad but it could be worst.

There is a fine line between loving your country and wanting nothing but the best for it and thinking you are better than everyone else.

When you are willing to kill people of another race, nationality or ethnicity because you perceive them to be a threat to you simply because of their race, ethnicity or nationality