Slavery was why the north and south were fighting, so it would be slavery
In the the Treaty of Brest-Litovsk Russia had to abandon
Finland, Estonia, Latvia, Lithuania, Russian Poland, Part of Belarus, Ukraine, Bessarabia, and Parts of the Caucasus to the Ottoman Empire
The Germans hoped to turn most of these countries into German satellite states.
In addition, Russia had to agree to pay about US$ 6 billion in reparations to Germany.
the answer to your question is a) they had advanced planning and developed effective military methods.
Most liked the idea of joining the USA and of course did not resist. It is said that they accepted it with a fatality like which they accepted small pox,tuberculosis and hook worms. the worst that happened was dogs barking at US soldiers passing through.
Is there a article to this?