The USA is far too strong a nation, with mostly-defensible borders, to ever be overwhelmed from outside. No less a strategic thinker than Isoroku Yamamoto may have said, 75 years ago, that it was his choice to not try to directly invade the mainland US, as there would be "a rifleman behind every blade of grass".
Well, that hasn't changed. There may be even more riflemen smoking hiding behind that grass. Nonetheless, we are in greater danger now than we ever were from the Nazis, the Imperial Japanese, or even the Soviet Union in it's armed-to-the-teeth heyday.
Today, the danger of the USA being conquered comes from folks already here. No invasion force will be required. The invading forces are already here. This article says that there are 2.6 million adherents to the Prophet Mohammed here. We already know that there are at least 12 million illegal aliens here, according to the Pew Polling folks, and considering the socialist slant of Pew, that number is likely underdone.
Very few Islamic folk will reject ANY part of of the Quran, even the parts which call for murderous tactics to convert non-believers to their faith. 109 verses certainly weren't a slip of Mohammed's pen. So, when the call comes, we can expect that the equivalent of the entire active duty military will seek conflict according to the wishes of their Imams. Taking the time-honored "three-percent" rule, which says that there are usually a hard core of a hostile population totalling 3 percent willing to fight and die, that means that there are about 80,000 Jihadists ready to martyr themselves upon the call of their Imams. If you give each Jihadi a probability of killing 5 people, that's close to 400,000 folks to write off when the Muezzin sings his song of Jihad. Sorta makes 9-11 look like a bad day on the freeway, eh?
Now for the illegals. 12 million or so. Some say many more. If you take 3% of those, that's almost 5 times as many folks. Whatziss you say, they're not bound by Jihad. Correctimundo, they are not, but at least 3% of them are hard-core criminals. This article says that 400,000 have been ordered deported for serious crimes (presumably felonies). They are potentially "guns for hire". With the Southwestern States awash in drug cartel cash, and most of those felons having done the bidding of the cartels at some point, there is real danger. Now we add the adherents of the La Raza Cult, those folks who believe that the USA illegally holds hispanic territory, and believes that a fight might be in order to restore it to Mexico. I don't find any numbers of La Raza, but together with their gangster cousins in the various arms of the drug cartels, there are thousands of armed nasties who would respond to calls to rise up.
The threat is here. It is a diversified, asymmetric threat. All it needs to wreak severe havoc here is a unified voice of leadership. The Jihadis are capable to making that call.
Considering this threat, and the fact that while in Madrassa, our President HAD to have read those 109 verses in the Quran, don't YOU suppose that his basic refusal to even USE the word Jihad or refer to Jihadis as terrorists, or even use the general term Islamic Terror, don't YOU think we have a problem, my friends?
I do. Stay armed. Stay ready. Act smart, but be ready to project offensive force in the blink of an eye.
Why offensive force? Why not duck and cover? It doesn't work with Jihadis, that's why.