The European Union agreed yesterday to begin talks with Ukraine and Moldova on bringing the countries into the 27-member organization. Ukraine applied for membership last February, four days after Russia's initial invasion.
Similar to NATO—for which talks of Ukraine's membership have not meaningfully progressed—the EU has a mutual defense clause. The condition would, in principle, require the EU to defend Ukraine's border with Russia, were Ukraine to eventually join. The formal accession process is likely to take years and requires wide-ranging conditions on Ukraine's side.
Hungarian Prime Minister Viktor Orbán left the room during the vote to allow for a unanimous decision, days after saying he would derail the bid (notably, EU officials separately agreed to unblock $11B to Hungary Wednesday evening).
In related news, Russian President Vladimir Putin signaled openness to a prisoner swap for two US citizens currently imprisoned in the country.