Hizbollah, considered by some experts to be the finest light infantry in the world, has a wide network in the U.S. that operates a cigarette smuggling business. These are likely Hizbollah.
They are left alone, because cig smuggling is considered a "soft" crime, since only one state or another gets beat out of some tax money.
So we have several thousand trained warriors here in the states smuggling cigs and raising literally millions of dollars.
If/when these guys decide to strike it won't be a picnic. They're not like the dimwitted sui-bombers or lone nuts like Malvo and co.
They are well trained, well coordinated and well armed.
Oh, most are operating falsely on legal documentation.
In other words, at some point a person (Abdul)migrated legally to the U.S. He had no connection to any terror group and no criminal record.
He gets all the right docs, license, green card, etc.
Then he sort of fades away, to be replaced by someone else going by the same name and using the same documentation.
The new "Abdul' is Hizbollah.
He may even(probably does) work at the same gas station or convenience store selling the same smuggled cigs, but he's a warrior of Allah.
Neat, eh?