STORY: The announcement that the U.S. and Germany will begin donating dozens of their main battle tanks to Ukraine's war effort, after weeks of diplomatic debate and speculation, is being heralded as a game changer by Kyiv.Germany says its overall goal is to send two tank battalions, which are typically comprised of three or four smaller units called companies, each with about 14 tanks apiece. The U.S. on Wednesday said it would send 31 of its most advanced battle tanks, the M1 Abrams. "Getting those vehicles will improve their ability to take ground. But, but I would be a little cautious about assuming that with them they will conquer the world."Stephen Biddle, adjunct senior fellow for defense policy at the Center for Foreign Relations, and professor of International and Public Affairs at Columbia University:“M-1 Abrams is widely regarded as the single best main battle tank in the world today. It's been around for a long time, but it's been upgraded repeatedly over the years, and it has performed in combat against Soviet and Russian made tanks very effectively. There's every reason to believe that it is a dramatically superior vehicle to the one the Russians are now fielding and to the ones that the Ukrainians are now fielding.”While Kyiv has praised the decision, Biddle doesn't expect the latest promised weapons to change the tide of the war. “The numbers that the Americans are talking about are not going to be militarily significant in and of themselves. All right. A couple of dozen tanks are not going to reverse the battlefield outcome in Ukraine. Hundreds are going to be needed. Now, the Leopard twos can be provided in those kinds of numbers, in part because lots of different European countries operate them.”The Leopard 2s are what Germany plans to supply to Ukraine.However, Biddle says the U.S. held back providing Ukraine with the M1 Abrams, initially out of the concern the Ukrainians wouldn't be able to handle the tank's complex logistical needs. There's also another catch: the Biden administration says the Abrams is meant for Ukraine’s long-term defense, and it will take months, not weeks, to arrive. That means they likely won’t be part of any expected spring offensives to break the deadlock in eastern Ukraine – where German intelligence believes Kyiv’s forces are taking casualties in the triple digits every day.