How far back?
Historically, the Swedes attacked the Russians via the Baltics, and Prussia also, as late as the end of the 18th Century.
How about the route every Russian knows about in great detail, Hitler’s run through the Ukraine. Today Ukraine has two armored brigades that have been sitting on the Russian border. They have 7 artillery brigades. The day after Ukraine has been admitted to NATO, NATO has these resources sitting on the Russian border with pretty much unlimited reserves. Can’t you see how dangerously provocative this would be? Why would we want to do this? I’m sorry Ukraine is in this position it has been in the last three hundred years. I’m sorry for Syrian Christians, the list is long. We are talking about NATO, which is Germany plus what, 70% of world GDP as allies. Like I’ve said before, would we allow 2 Warsaw Pact armored brigades sitting in the deserts of Chihuahua? Hell no, we wouldn’t have tolerated it. Where was the world outcry when Biden, Obama and the US State Department was raping Ukraine economically and using it as their personal vassal state, and probably still are? Is that what everyone is so anxious to screw around with a potential WWIII over, keeping the US corrupted Ukrainian oligarchs in power?