Elaborate?
Advanced nations don't engage in traditional warfare with one another.
A perfect cocktail of economic sanctions and foreign investment, technological infiltration, proxy wars and sleeper cells can mitigate the oceans as a buffer.



Unfortunately he's right. Civilians have always been casualties of in every war in human history. Ironically drone strikes are used to reduce the number of casualties in war. Before drone strikes we use to destroy entire neighborhoods to get to our target . Now not only do we save American soldier lives, but we also minimize civilian damage

That's not the same as a military force invading the USA and taking away our freedom. So my point still stands.
But I do get what you're saying. But again there is no force in the world that can invade Continental America with a military force that can take away our freedom. The stuff you listed are not taking away our freedom.
I think Chinese hackers grabbing ahold of American technological infrastructure would go a long way in crippling us.
Or a Russian sleeper cells letting off dirty bombs in metropolitans
Not that it is likely but
There is no need for a military force to do real damage, it's archaic.
Cyber Wars. The Gov has been saying for years that hackers have been targeting the US power grid.Elaborate?