Back in ancient times, Invasions of large armies happened quite regularly, as one society tried to conquer another, take their land and enslave the other population. Nearly all invasions were land-based, few maritime invasions were succesful. The Muslim conquest of Spain across the Mediterranean would be one exception, but they eventually got pushed back to Africa. In colonial times, the Spanish tried to invade England, but unfortunately most of the ships got sonk in a storm.
The last BIG invasios took place in WWII The Nazis invaded all of continental Europe, quite successfully for a while. The tactic was Speed & Surprize, the BLITZKRIEG. However, they never were able to invade Britain, just a short hop across the English Channel. Nor could they invade the Scandinavian countries across the North Sea. They remained neutral for the duration of the war. Nor could they invade Switzerland, mountains are no good for tank battles. They tried and failed to invade Mother Russia, but it was too big and the weather too harsh.
The final invasion of WWII was a maritime one, D-Day. It had to be carefully concealed for time and location, and even so was extremely costly. The Brits never could have pulled it off by themselve, it took the Amerikan entrance into the war to pull it off.
Nowadays, maritime military invasions between large powers are impossible. Neither the Ruskies or the Chines could invade the FSoA, nor could the FSoA invade them. There can be no surprise, satellites would pick up the ships being loaded up before they ever left port. Cruise Missiles would sink the ships before they got anywhere near enough to unload. So fear of invasion as a rationale for a large military is a phantom threat.
Invasions still happen of course on the military level, of small countrries by larger ones. The Ruskies tried to invade Afghanistan before we did, bothg attempts failed. In antiquity, Alexander the Great tried to invade Afghanistan, he failed too. It's where large armies go to die. We tried to invade Vietnam and Iraq, those invasions failed also. Military invasion is quite hopeless these days, but there other forms of invasion.
Economic invasion has been the primary method of taking control since the end of WWII by all the main powers. The Chinese hold most of East Asia in thrall, the Ruskiess hold most of Easterb Europe and Central Asia and the FSoa holds Central and South America and Western Europe. Africa is a perpetual battleground for all the major powers.
The other form of invasion moving in the other direction is migration, both legal and illegal. This is slower than economic or military invasion, but nowadays much more effective. It's changing the demographics of all the Western countries and Mother Russia too. Not so much China, which until now has had plenty of its own people to do the scut work for the Elite. Internal political problems and eventually revolutions will emerge from this.
I dout we will ever see direct military confrontation with the Ruskies or the Chinese. Even the Illuminati know that the War Games scenario, Global Thermonuclear War cannot be won. "The only solution is not to play". So they continue to thrust and parry, trying to edge out an advantage here or there. Meanwhile, inside their own borders, social dissolution proceeds apace. The danger of war we all face comes from within, not from without.
The question this leaves us with is which of the 3 main powers will be FIRST to descend into anarchy and Civil War? Opinions welcome.