Babe the US did not send forces into Ukraine. Russia did. The US did not "threaten the territorial integrity of Ukraine". Russia did. Ukraine did not join Nato. Maybe you could make an argument that the US has exerted economic pressure on Ukraine but you can definitely make that argument for Russia.
It just doesn't make sense to paint the US as the primary aggressor in this instance.
While, of course, people can have different views or opinions about this, as you please, I observe that you get one story in Western media and another in Russian media. Russian media gets more play in Europe, in NATO countries like Germany, on this issue than our media gives it.
As I outlined above, there is reason to believe that, when signing the 1994 agreement, the Russians believed they had "their" people in charge in Ukraine. In their view, the agreement was only going to be good if the US and GB kept their mitts off Ukraine. The agreement actually gave no "teeth" or "enforcement" powers except that if there would be a dispute, Russia would have to be included in any settlement at some bargaining table. In other words, if we did not keep our mitts off Ukraine, Russia would do what it takes to defend its vital interests.
And that is what Russia did.
The important and hopeful emerging fact of it all is that it appears that Ukraine's public still wants non-alignment and does not want to join NATO. What they want is real independence, and the benefits of doing business with both sides. It's a position like what the United States took in the era of initial independence. We did not want to have to "align" with warring Europeans, like Britain and France, so we had a foreign policy centered on the idea "Alliance with none, commerce with all."