The West finally starts rolling out the big guns for Ukraine

The United States and its NATO allies have ramped up the delivery of tanks, helicopters, and heavy weapons to Ukraine as the country's forces prepare for large-scale battles against Russian troops in the Donbas region of eastern Ukraine.

The new arms deliveries represent a stark shift from Western support for Ukraine in the earliest days of the war, when US and European officials, unsure of how long Ukraine could hold out against a massive Russian invasion, were wary of delivering heavy weapons that could in turn fall into Russian hands. The deliveries also reflect a shift away from defensive systems like anti-tank rockets to more offensive weapons that Ukraine needs at a critical stage of the war.

The Czech Republic opened the floodgates earlier this month by shipping tanks to Ukraine, becoming the first NATO country to do so since Russia launched its invasion on Feb. 24. The Czech Republic has also sent Ukraine infantry fighting vehicles and artillery systems.

Other NATO countries have followed suit with their own shipments of high-end military hardware across NATO borders into Ukraine. Slovakia sent Ukraine an advanced S-300 air defense system, and the United States on Wednesday announced it would supply Ukraine with an additional $800 million worth of military hardware. That shipment includes 11 MI-17 helicopters, 200 M113 armored personnel carriers, 100 Humvees, 300 Switchblade "kamikaze" drones, heavy howitzers, thousands of shells, and other munitions.

During the first phase of the war, many Western officials believed Kyiv could quickly fall to Russian forces in a matter of days, prompting them to balk on sending heavy weapons to a government they were unsure could survive.

That all changed after Russia's massive offensive in northern Ukraine ran aground, thanks to stiff Ukrainian resistance backed by Western supplies of anti-tank weapons and other small arms, as well as clumsy tactical missteps by the poorly equipped Russian forces.

The transfer of heavy weapons to Ukraine is far from simple. In addition to the heavy vehicles and weapons themselves, any such transfers to Ukraine require a potentially long logistical tail to back up, including training, spare parts, and mechanics to keep the vehicles operating in the war zone. (Russia has threatened to attack US and NATO weapons deliveries headed into Ukraine.)

"The tank is not just a rental car," said Ben Hodges, former commanding general of the US Army in Europe. "Whenever you're talking about transferring any sort of mechanized or armored vehicles, you have to also think about spare parts, maintenance packages, training, fuel, ammunition … to make sure they can keep things running."

Nevertheless, a senior US defense official said on Monday that several allied nations were still considering delivering tanks to Ukraine, mostly Soviet-era variants that troops in Kyiv had already been trained on. "This is equipment that Ukrainians probably are already familiar with, so the time to train on it would be relatively quick," Hodges said.

The logistical complications have prompted some Western governments to withhold delivering larger supplies of heavy vehicles to Ukraine, despite pleas from top Ukrainian officials for more support for their outgunned and outmanned forces.

Others, particularly some politicians in Germany, fear that upgrading Ukraine's military with heavy weapons could turn the West into a target for further Russian aggression. That debate has reportedly sparked rifts within the ruling coalition in Germany.

Disclaimer: This article first appeared on Foreign Policy, and is published by special syndication arrangement