There is only one reason that we have not experienced as many attacks like this as Britain has. It is not because our government is protecting us, (because God knows they suck at everything they do except for making life hard for working Americans).
The one reason for our relative safety is that we are an armed populace. Period.
That's a factor, to be sure, but it's also true that America has a moderating influence on extremists. I'm not saying that this effect is sufficient to eliminate Islam extremists, but having the freest society on earth does help, because people see that the average everyday American is not some kind of demon.
In America, most people want to live their lives as they please, and be left alone if they please. Most people instinctively want this.
In addition to the deterrent of an armed populace, being in the land of the Free does have a positive effect, IMHO.
Having said that, hoever, there can be no doubt that what rigelkentaurus said about Muslim "critical mass" is true.
This is a major reason that keeping Muslim immigration to a bare minimum is an ideal policy for defending our homeland against the threat of radical Islam.
Is London really approaching 15% Muslim population? That's remarkable. I'd say Europe has a growing problem on its hands, and there's no reason the US should follow suit with such a dangerous "open door" policy with respect to immigration.
Making sure that immigrants assimilate—and are motivated to—is a critically important concept which is neglected by the naive Progressive crowd, who seem to think that singing "Kumbayah" together is sufficient to keep the boogeymen away.
Those who don't want to assimilate should not be welcome as immigrants.
I, for one, can't wait for the massive smackdown which is about to be administered to the Democrats by the US Supreme Court, when they finally uphold the President's immigration EO's...