Reply #41: I believe that in WWII, the Brits would have resisted an invasion...

[spin]

with any weapon that was available.


Remember this famous quote:

We shall defend our island, whatever the cost may be, we shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender.
Winston Churchill
http://www.brainyquote.com/quotes/quotes/w/winstonchu161337.html

The British did have a Home Guard, the LDV.

Initially the LDV were poorly armed, since the regular forces had priority for weapons and equipment. The LDV's original role had largely been to observe and report enemy movements, but it swiftly changed to a more aggressive role. Nevertheless, they would have been expected to fight well-trained and equipped troops, despite having only negligible training and only weapons such as pitchforks and shotguns (a solid ammunition for shotguns was developed for this purpose) or firearms that belonged in museums. Patrols were carried out on foot, by bicycle, even on horseback, and often without uniforms, although all volunteers wore an armband that said "LDV". There were also river patrols using the private craft of members.<27> Many officers from the First World War used their Webley Mk VI .455 revolvers. There were also numerous private attempts to produce armoured vehicles by adding steel plates to cars or lorries, often armed with machine guns.<28> Some even had access to armoured cars, though these were makes no longer in service with the regular army.<29>
http://en.wikipedia.org/wiki/Home_Guard_%28United_Kingdom%29#Equipment_and_training

Had the Germans been able to pull off an invasion (questionable at the best), the firearms sent by Americans would have made little difference in the outcome. Still, the Brits would have fought and died to defend their homeland.

Invading the United States was a far different matter.

Why The Japanese Did Not Invade After Pearl Harbor

In 1960, Robert Menard was a Commander aboard the USS Constellation when he was part of a meeting between United States Navy personnel and their counterparts in the Japanese Defense Forces. Fifteen years had passed since VJ day, most of those at the meeting were WWII veterans, and men who had fought each other to the death at sea were now comrades in battle who could confide in one another. Someone at the table asked a Japanese admiral why, with the Pacific Fleet devastated at Pearl Harbor and the mainland US forces in what Japan had to know was a pathetic state of unreadiness, Japan had not simply invaded the West Coast. Commander Menard would never forget the crafty look on the Japanese commander's face as he frankly answered the question. “You are right,” he told the Americans. “We did indeed know much about your preparedness. We knew that probably every second home in your country contained firearms. We knew that your country actually had state championships for private citizens shooting military rifles. We were not fools to set foot in such quicksand.”
http://twinbuttebunch.org/index.php?fuseaction=articles.japanese

But that was then. Today, I don't see major invasions of countries being used as much as economic warfare.