Vladimir Putin claims to be scaling back his war aims in Ukraine, for now. According to the new line, the war was only ever about “liberating Donbas” (Donetsk and Luhansk oblasts in Eastern Ukraine), and please ignore the obvious attempts at regime change and the capture of Kyiv. This new line leaves the territories that Russia has seized outside of Donbas in a somewhat awkward position. Under the initial Russian plan—which was, undeniably, regime change—they could have been just another province in a Ukraine under Russian domination. However, if regime change is no longer in the near future, what is to become of them? Russia could run away and Ukraine might recapture some of these territories, but what if the front stabilizes? They could conceivably be “traded” back to Ukraine as part of some peace deal, but in exchange for what?
The two obvious options for what to do with these areas is to turn them into new “peoples’ republics” or to just incorporate them into Russia. The area where this question is most obviously unresolved is in the city and province Kherson. Kherson city is the largest city Russia has captured, and the province has critical strategic value. The Dnieper river, the fourth-longest in Europe, passes through the province. The river bisects Ukraine, and the city of Kherson was founded as a port near its mouth where it empties into the Black Sea. If Russia keeps control of Kherson, it could permanently deny the full use of this waterway to an uncooperative Ukraine and also rob Ukraine of one of its ports.
The most important thing that Kherson has and Russia needs is water. A massive irrigation canal branches off from the Dnieper about 40 miles upstream from the city of Kherson. This canal was the main source of fresh water for the Crimean Peninsula (which Russia has claimed as part of its territory since 2014). In 2014 the Ukrainians blocked the canal off (no sense in sending water to the forces occupying their territory), and occupied Crimea has suffered from a chronic shortage of water since the Russians took it. The Russians have been furious about this, and one Russian diplomat equated the move with genocide. One of the first things the Russians did when they occupied Kherson was re-open this channel and restore the flow of water. Now the reservoirs in Crimea are full again, but Ukraine may shut the flow off again if Russia leaves Kherson. Leaving the canal open might be something Russia can negotiate for in a peace deal, but that would still give leverage to Ukraine in any future standoff with Russia (assuming Russia holds on to Crimea).
For these reasons, Kherson, especially southern Kherson, is one of the bits of Ukraine that Russia may insist on keeping one way or another, regardless of the outcome of the fighting elsewhere or the needs for any future peace deal. If Russia is going to try to hang onto it, then it will probably start to build the political justification for keeping it.