Calls for West to set its own red-lines for Russia

Perhaps we've not done this because the West's next red-line would actually be within Russia and it would look a bit stupid and Totalitarian (something the West desperately needs to try and avoid) telling the Kremlin that if it operates within its own borders it would be violating Western resolutions.

That said WW2 was based upon one such piece of idiocy. Hitler was actually only operating within pre-1918 borders so from a German perspective Germans were just moving in Germany, It's only the West and the Versailles "agreement" that Lloyd-George said was ridiculous and the Germans did not accept that Churchill was able to draw his fictitious lines through countries that didn't even exist from a German perspective.