Ukrainian President Volodymyr Zelensky will address the US Congress today as he uses the West’s great legislative bodies as a global stage to orchestrate support against Russia’s crushing invasion.

Zelensky’s livestreamed address into the US Capitol will be among the most important in a unique and very public strategy in which he has invoked Winston Churchill, Hamlet and the power of world opinion in his fight to stop Russia.

Nearing the three-week mark in an ever-escalating war, Zelensky has used his campaign to implore allied leaders to “close the sky” to prevent the Russian airstrikes that are devastating his country. It’s a singular request and now a rallying cry in popular culture.

It has also put Zelenskyy at odds with US President Joe Biden, whose administration has stopped short of providing a no-fly zone or the transfer of military jets from neighboring Poland as the US seeks to avoid a direct confrontation with Russia.

Instead, Biden will deliver his own address following Zelensky’s speech, in which he is expected to announce an additional $800 million in security assistance to Ukraine, according to a White House official familiar with the matter.