Slovakia has transferred an S-300 missile defense system to Ukraine, fulfilling one of Ukrainian President Volodymyr Zelensky's top requests to help the country defend itself against Russia's bombing campaign.
Why it matters: Zelensky pleaded in an address to the U.S. Congress last month for the U.S. and its European allies to impose a no-fly zone or give Ukraine the ability to "close the skies" itself by facilitating the transfer of Soviet-era fighter jets or anti-aircraft systems.
