Problem is it has already started. Reid (shoe-bomber) was an American IIRC. The beltway snipers - Americans. Recent criminals caught in the LA area w/ national guard info - Americans. Islamofacists have penetrated our prison systems - what better targets to harvest 'dead enders' from.
Found reference to the local (Chicago area) bomb threat
Purple Line evacuated after bomb threat
http://www.suntimes.com/output/news/cst-nws-bomb13.html
When I was in high school, my history teacher, who was Jordanian, was a rabid supporter of the Palestinian cause and tried to recruit me into the Arab-American Association, just because I am of Lebanese descent (gotta love the protest babes!). He assumed that I would think like him, although one of my best friends at the time was a Jewish kid in my class. I had more in common with him than I did with "Ali".
I can very easily see this kind of recruitment happening on an even more sinister scale these days.
When it happens, we can pin some blame squarely on the government. When they failed to charge Jihad Johnny with treason, they did our country a great disservice.