Christine who won last year wasn't from the US - I think that a good 1/2 of the top 32 were from other countries (don't quote me on that thought I may be wrong... I remember that there were a lot of people that I didn't realize were European until the talk about their entries).
I may be wrong, but I believe that Christine also stated that English was not her first language. So it not only doesn't matter what country you're from, or if you're not the most fluent writer of English, as long as you've got a good spell/grammar checker you've got a shot!
It's submitted,and it feels so good
It's submitted, 'cause I understood
There's one perfect fit
And, sugar, this one is it
I'm just so excited
'Cause I'm submitted
Hey, hey