Compare the two land masses, North America and Eurasia.

The USA is huge, and it has enormously long coastlines on both sides, so it dominates both the Atlantic and the Pacific. Ideal conditions for a global empire.
But it's tiny compared to Eurasia. And that's why a peaceful and stable trading union from Lisbon to Vladivostok (and Shanghai) has to be prevented.
-----------------
*There is a declassified document (can't locate it right now) in which the US states explicitly that it's a foreign-policy priority for Germany and Russia to be kept apart and at odds with each other, not allowed to get too cosy. And right now, German industry is losing billions every year due to the sanctions imposed on Russia by the US (which of course the entire EU also has to follow). A lot of German capitalists are not happy at all about that, though they have to keep their objections muted. Ever since the early 90s, Russia has been one of Germany's most important trading partners.