Jason, I think it’s wonderful that you’re learning a little about real US history. Far too many US citizens know only the Disney version they’re given in High School, which is almost entirely a fantasy. As for immigration, you may want to educate yourself further on this important topic as you may discover your views will change significantly once you become aware of the data on this topic. As for “international terrorism” we can note that most of the terrorist incidents in US history have been, and continue to be, home-grown. 9/11 was a rare anomaly that has been played up as if it were normal in order to justify enormous infringements on civil liberties.
It turns out that the things US citizens are afraid of are, as has always been the case, spurious straw men invented by those who have an interest in keeping the population ignorant and fearful because under these conditions people are so very easy to manipulate.