What happens next in the Ukraine war

theweek.com: After the fall of Sievierodonetsk, Ukraine is entering the next phase of its defense against the Russian invasion. As the war drags on, Ukraine and its allies are facing a new set of decisions about how best to move forward. Here's everything you need to know:

What's happening around Sievierodonetsk?

The city of Sievierodonetsk fell to Russian forces last week after one of the bloodiest battles of the war. Ukraine still holds Sievierodonetsk's twin city, Lysychansk, which is located to the west on the other side of the Siverskyi Donets River. During the battle, Russia destroyed the three main bridges linking the two cities, making it unlikely that they will launch an assault across the river. Instead, Russian forces are pushing up from southwest of Lysychansk, hoping to encircle Ukrainian forces in the city and its surrounding area.

The U.S.-based Institute for the Study of War assesses that Ukraine is likely to "abandon Lysychansk ... and conduct a fighting withdrawal to more defensible positions." Some Russian milbloggers and an official from the Luhansk People's Republic have claimed that this withdrawal has already begun. If Ukraine surrenders Lysychansk, it will leave Russia in full control of Luhansk Oblast. The ISW suggests this withdrawal could signal a Ukrainian attempt to "force the Russian offensive to culminate prematurely."

Jonathan Powell, who served as chief of staff to British Prime Minister Tony Blair, wrote for The Guardian that Russian President Vladimir Putin might be "ready for serious negotiations" once the battle of the Donbas wraps up. If Putin is satisfied with Russian territorial gains, Powell opines, "he could declare a ceasefire in place, as he did in 2014," which "would leave Ukraine with another frozen conflict" and throw a wrench into any future negotiations about Ukrainian membership in NATO or the European Union.

How many civilian casualties has Ukraine suffered?

According to the Office of the United Nations High Commissioner for Human Rights, 4,731 Ukrainians have been killed and 5,900 injured since Russia invaded the country on Feb. 24. This number includes 191 deaths and 777 injuries on territory controlled by the Russian-backed separatist republics.

Russian forces have recently stepped up their attacks against Ukrainian civilian targets. On Monday, a Russian missile strike on a shopping mall in Kremenchuk — located in central Ukraine far from the front lines — killed at least 20 civilians. Russia claimed its missiles struck a weapons cache, causing a fire that then spread to the mall, but Ukrainian and independent sources have produced evidence contradicting this narrative.

Ukrainian government official Vadym Denisenko said Sunday that Russia had begun indiscriminately launching large numbers of missiles into Ukrainian cities.

How's Ukrainian morale?

Despite these attacks on civilians, Ukraine's fighting spirit remains unbroken. Fifty-three percent of Ukrainians said it was "very" or "extremely" likely that the war would end with Ukraine in control of Crimea and the entire Donbas, a Wall Street Journal/NORC poll found. (The NORC surveyed 1,005 Ukrainians between June 9 and June 13 with an error margin of four percent.)

Most Western observers disagree. Former Secretary of State Henry Kissinger argued at Davos that Ukraine should give up territory now in order to secure a peace deal with Russia. A European Council on Foreign Relations poll conducted in 10 European countries between Apr. 28 and May 11 revealed that 35 percent of respondents agreed that the goal should be to "stop the war as soon as possible, even if it means Ukraine giving control of areas to Russia." Only 22 percent said it was more important "to punish Russia for its aggression, even if it means that more Ukrainians are killed and displaced." Even President Biden refused to rule out letting Russia keep some of the Ukrainian territories it controls.

Russia has also warned there could be severe consequences if Ukraine pushes for total victory. On Tuesday, Russian Prime Minister Dmitry Medvedev said that if Ukrainian forces make any "attempt to encroach on Crimea," it would be considered "a declaration of war on our country." This threat dovetails with Russian President Vladimir Putin's claim that he would use nuclear weapons to defend Russia's "sovereignty" and with Russian military doctrine, which allows for a nuclear response to conventional attacks that threaten the "existence of the state."

The Ukrainian people are having none of it. Eighty-nine percent of respondents told the NORC that trading land for peace was "unacceptable." Neither is Ukrainian President Volodymyr Zelensky — Although the Ukrainian president said last month the war "will only definitively end through diplomacy," he also equated territorial concessions to Russia with the appeasement of Nazi Germany.

What's going on with NATO?

NATO on Wednesday formally invited Finland and Sweden to join the military alliance, after Turkey agreed to drop its opposition to the countries' prospective membership. "The accession of Finland and Sweden will make them safer, NATO stronger, and the Euro-Atlantic area more secure," the alliance said in a statement.

This latest expansion of NATO also prompted Zelensky to raise the issue of NATO membership for his own country. Speaking at a NATO summit in Madrid on Wednesday, Zelensky called on the alliance to find "a place for Ukraine in the common security space" and asked whether his country had "not paid enough" to secure membership in NATO.

In a rare diplomatic win for Russia, Syria announced Wednesday that it would formally recognize the Luhansk People's Republic (LPR) and the Donetsk People's Republic (DPR) — a pair of Russian-backed separatist entities in eastern Ukraine — as independent nations.

Is Russia able to sustain its war effort?

Some Russian hardliners have lobbied the country's government for a full declaration of war against Ukraine, a move that would enable the full mobilization of Russian reserve forces. So far, though, such a declaration has not been forthcoming. Instead, Russia is calling up reserve units piecemeal, refusing to rotate frontline units out of the fighting, and filling gaps in its ranks with poorly trained Chechens and volunteers from the separatist republics. Russia also appears to be having trouble replacing dead officers.