Market Data 
Ukraine has dealt a massive blow to Russia’s Black Sea Fleet in Crimea.
Russia has retained control of Crimea since invading and annexing the peninsula in 2014 and secured Sevastopol as the headquarters for its Black Sea Fleet.
But following Russia’s full-scale invasion in 2022, Ukraine has repeatedly struck back in the region, destroying or damaging around half of the Russian fleet’s warships, including one submarine, according to publicly available information.
It has used aerial drones, sea drones, and anti-ship missiles against the fleet and the Kerch Bridge, to often devastating effect. Ukraine’s campaign even pushed Russian warships to withdraw from Crimea to bases in the port cities of Feodosia, on the far side of Crimea, and Novorossiysk, in Russia.
It is degrading the peninsula as a key logistics route to its occupying forces across southern Ukraine and tainting its attractiveness to Russians as a summertime beach destination. But if Ukraine hopes to follow through on its pledges to retake Crimea, it will need a huge assault force steeled for what’s likely to be the hardest fight of a bloody war.
“Retaking Crimea would be extremely difficult because Crimea is essentially an island,” Mark Cancian, a retired US Marine Corps colonel who’s a senior advisor at the Center for Strategic and International Studies, told BI.
“An amphibious assault is impossible because Ukraine lacks ships to carry large numbers of troops and their heavy equipment,” he said, adding: “Further, Russia still has long-range aircraft and submarines, which are essentially invulnerable at sea.”
Russia has a vast military infrastructure across Crimea that will have to be severely damaged in order for Ukraine to have a chance to seize it back, according to Basil Germond, an expert in international security at Lancaster University in the UK.
He said Ukraine “would first need to prepare the terrain by destroying or seriously degrading all of Russia’s air, air defense, missile defense, communication, and electronic warfare equipment and capabilities in Crimea and perhaps the Kerch Bridge.”
A challenging location
Reaching Crimea has proven challenging due to its location away from the front lines, Russia’s heavily fortified defensive lines, and Ukraine’s lack of manpower and airpower, military experts and analysts told BI.
“Crimea is deep inside Russian-occupied territory and far from the current front lines,” Cancian said.
And Russia has heavily fortified its 600-mile front line with anti-tank ditches, mazes of trenches, ‘dragon’s teeth’ barricades, and minefields, with much of its defenses in northern Crimea.
“The Russians are heavily fortified and well-defended in these areas, and it will take time for the Ukrainians to break these defenses,” said Mark Temnycky, a nonresident fellow with the Atlantic Council’s Eurasia Center, who added that troops are proceeding with “extreme caution.”
Without the options to ferry a large assault force by air or water, Ukraine will be forced to attack through Russian defensive lines to approach Crimea. Furthermore, were Russia to lose its hold on Kherson, it could mine and concentrate firepower on the few land approaches to Crimea, using similar tactics to those that stopped Ukraine’s 2023 counteroffensive.
“Without an amphibious naval force to land in Crimea, how can Ukraine project enough troops onto the peninsula to claim its control?” said Germond of Lancaster University.
Ukraine has resorted to hitting Russia’s air defenses in Crimea with missiles and long-range weapons, including US-supplied Army Tactical Missile Systems, known as ATACMS.
Last month, war analysts from The Institute for the Study of War said Ukraine’s sustained attacks against Russia’s air defenses could render Crimea untenable as a military staging ground.
But they also noted that Russia was likely placing military facilities near civilians to try to deter further Ukrainian strikes.
Last month, Russian-installed Sevastopol governor Mikhail Razvozhaev claimed that a Ukrainian strike killed four people and injured 151 people.
“Millions of citizens live on the peninsula, and the Ukrainians do not want to harm the civilian population,” Temnycky said.
Any Crimea assault comes down to numbers. Russia aims to commit 690,000 troops to the war by year’s end, a large build-up that could bolster the Russian troops and Ukrainian conscripts on Crimea, a force perhaps 60,000- to 80,000-strong. It’s likely Russia could commit well over 100,000 were Crimea to be threatened.
To have the best chance to push through their defenses, Ukraine is likely to need a well-supplied force three to five times the size of the defenders — a guideline that would balloon any operation to many times the size of the 2023 counteroffensive.
Benjamin Friedman, policy director at the Defense Priorities think tank, said that Ukraine lacks the manpower and air cover required to go on the offensive in a “major way.”
“Even with F-16s, I don’t think Ukraine has the ability to provide its ground forces effective close air support, given Russian air defense capability,” he told BI.
Retaking Crimea
Despite the battleground challenges Ukraine faces, some experts believe it could retake Crimea with enough weapons, troops and time.
This would involve crossing the Isthmus of Pereko, separating Crimea from mainland Ukraine, or crossing the marshes to the east, called Sivash, to reach Crimea.
“That’s what happened during World War II, when the Germans captured Crimea in 1942, and the Soviets recaptured it in 1944,” Cancian said.
However, to do this, Ukraine first needs to break through Russia’s Suvorikin Line, a complex system of defensive fortifications and obstacles across Russian-occupied territory in southern and eastern Ukraine that Ukraine has never pierced through. A force that advances through this also faces a high risk of becoming bottlenecked on the few land approaches and destroyed by the short- and long-range firepower Russia would almost be certain to bear.
According to Sergej Sumlenny, founder of the German think tank European Resilience Initiative Center, the question now is “when Ukraine will accumulate so much firepower, not just artillery, but also air force, so they manage to push through these defensive lines and then reach the operative space” of Crimea.
If and when Ukrainian soldiers do reach Crimea, Sumlenny said, they will be able to destroy the Kerch Bridge and the last ferry road over the Sea of Azov, cutting off all of Russia’s supply lines to the peninsula and isolating Russian forces. Using long-range missiles to cut-off supply lines was a crucial element of Ukraine’s grinding and successful liberation of the city of Kherson in late 2022.
Sumlenny added that Crimea has historically been vulnerable to offensives.
“There is no case in history when anyone could defend Crimea from an attack,” he said.
In 1921, the Soviet Union’s Red Army crushed the White Russians and took control of the peninsula, and in 1941, the Axis powers invaded the Soviet Union during Operation Barbarossa, with their land forces laying siege to Sevastopol.
The Red Army launched a massive counter-attack in late 1943 with 2.6 million men that pushed the Germans back and weakened their hold on Crimea. After two and a half years of German occupation, a Soviet force of over 450,000 regained control of Crimea in 1944.
It was transferred to Soviet Ukraine — one of the republics of the Soviet Union — in 1954, until the dissolution of the Soviet Union and Ukrainian independence in 1991.
Finally, in 2014, Russian forces invaded and occupied the peninsula before annexing it.
“If you look at all the cases when armies were clearly ready to fight and defend their positions, we can say that Crimea is practically an undefendable fortress,” Sumlenny said.
“So, from my perspective, the moment the Ukrainian army will appear on the land bridge — the Isthmus of Pereko — between Crimea and the rest of Ukraine, the Russians will face a very simple choice,” he said, “either they retreat immediately from Crimea or get slaughtered or captured.”
Other experts, however, struck a more cautious tone.
Temnycky said a full-scale invasion to try to retake Crimea is “very unlikely” due to the huge Ukrainian losses that would result.
Friedman, meanwhile, said such an operation would require a “cataclysmic Russian collapse,” which he said is “extremely unlikely though not impossible.”
Indeed, there have been fears that Russia would consider nuclear force if its troops were on the brink of losing Crimea.
Cancian said that “because of its difficulty, retaking Crimea would be the last event of the war, not an intermediate event.”
