In the middle 1650s under Tsar Alexei, Muscovite forces, allied with Cossacks in many places, occupied the eastern two-thirds or so of the Polish-Lithuanian commonwealth, in a period the Poles called the "potop" or "deluge". Despite being simultaneously ravaged and occupied by the Swedes in the west, Poland-Lithuania ended up recovering most of its territory, and at the Treaty of Andrusovo Muscovy only ended up keeping the left bank of the Dnepr and Kiev.
So, how could Muscovy manage to hold onto the territory it occupied in OTL (see map) in perpetuity throughout the seventeenth and eighteenth centuries? What effects would this have had on Muscovy, European and Eurasian power politics and ethno-national and religious evolution & demography within this precociously expanded Russian state?
I see assets and liabilities for Muscovy in these acquisitions -
The assets are greater proximity to the markets of central and southeast Europe, greater population, and vast new cultivatable lands across the entire Ukraine. The could arguably lead to greater continent-wide influence of Russia even from before the OTL reigns of Peter the Great, Elizabeth and Catherine. Over the centuries, the main ethnic identity throughout the entire Ukraine and Belarus may end up as Great Russian as in Moscow and the Volga, if all these territories go through more of the early modern age under a single sovereignty.
On the downside - Muscovy has more Cossacks and a wider area to pacify. It is also going to be taking direct punches and raids from the Ottomans along its southern borders that OTL Poland-Lithuania was a buffer against.
Additionally, whether under Polish, Swedish or Habsburg leadership, the Muscovite state will more likely have to contend with a more compact and cohesive western Poland, with revanchist territorial objectives against the far western reaches of Russia including Lvov and Vilnius.
Thoughts?
