In one of the most significant escalations of military support to Ukraine from a NATO member since the Russian invasion, Polish President Andrzej Duda on Thursday became the first leader from the security alliance to pledge fighter jets to Kyiv.

Duda announced that four MiG-29 fighters will be handed over to Ukraine in the coming days -- the rest, he said, are being serviced and will likely be handed over successively. Four might sound a modest number, but it is a monumental step from a year ago, when a NATO member sending such sophisticated lethal support to Ukraine was politically unthinkable.