Washington(CNN) A war-weary Ukrainian President Volodymyr Zelensky, speaking from his office in Kyiv, called on the United States to do more to protect his country and people in a dramatic address to American lawmakers Wednesday.
It was an extraordinary appeal to the world's largest military and financial power at a critical moment. Russian forces are intensifying their assault on Ukraine, including its capital, and the future of the conflict could depend on rushing additional American aid to Ukraine's beleaguered troops.
Zelensky, wearing stubble and an army-green T-shirt, was speaking as his team is working to negotiate an end to the violence with Russia, talks that haven't yet produced peace but have shown recent signs of progress.
His speech had an audience well beyond the congressional auditorium, where senators and representatives have been largely united in wanting to do more for Ukraine. It was also aimed squarely at the White House, where President Joe Biden unveiled new assistance later Wednesday.
Speaking directly to the President, in English, Zelensky said as his speech concluded: "Being the leader of the world means being the leader of peace."
When it was his time to speak, Biden thanked Zelensky for his speech, calling it a "convincing and significant" address.
Here are six takeaways from Zelensky's address to Congress and Biden's response:
While Zelensky said he was grateful to Biden for his "personal involvement" in confronting Russia, he made clear that Ukraine needs more help from Washington to keep up the fight.
He asked the United States to step up its sanctions against Russia. But the centerpiece of his address was a dramatic appeal for help defending Ukraine from Russian aerial bombardments, including calling for a no-fly zone.
"Russia has turned the Ukrainian sky into a source of death, for thousands of people," he said. "I need to protect our sky. I need your help."
Fully aware that a no-fly zone is something neither Biden nor most members of Congress support, he also offered an "alternative" — new air defense systems that would protect against strikes and new aircraft for his pilots to use in defending its airspace.
"Aircraft that can help Ukraine, help Europe, you know that they exist, and you have them. But they are on Earth, not in Ukrainian sky. They do not defend our people," Zelensky said.
Biden inched no closer to agreeing to Zelensky's biggest requests in his remarks. But he did seek to underscore what the United States has done and announced almost $1 billion in new military assistance, which he called "unprecedented."
It was an attempt to convey how he was working to help Ukraine defend itself, even as Zelensky and certain US lawmakers press for him to do more.
"Together with our allies and partners, we're going to stay the course," Biden said. "We'll do everything we can to push for and end this tragic, unnecessary war. This is the struggle that pits the appetites of an autocrat against humankind's desire to be free."
Biden announced new shipments of anti-aircraft and anti-armor systems, small arms and ammunition, along with drones that Ukraine has also been requesting. As Biden was listing each type of equipment and technology, it was evident he wanted to demonstrate exactly what the US was willing to provide short of planes or a no-fly zone.
"The American people are answering President Zelensky's call for more help, more weapons for Ukraine, more tools to fight Russian aggression," he said.
Biden ended his speech without making any specific mention of Zelensky's request for a no-fly zone or fighter jets.
Appealing for help for his besieged country, Zelensky harkened to two seismic events in American history: the attack on Pearl Harbor that thrust the US into World War II, and the terror attacks on September 11, 2001, which began a new War on Terror.
"Remember Pearl Harbor, terrible morning of December 7, 1941, when your sky was black from the planes attacking you. Just remember it. Remember September 11th, a terrible day in 2001 when evil tried to turn your cities, independent territories, into battlefields. When innocent people were attacked, attacked from air, just like nobody else expected it, you could not stop it. Our country experiences the same every day. Right now, at this moment, every night for three weeks now," he said.
Elsewhere in his address, Zelensky also evoked Mount Rushmore and Dr. Martin Luther King Jr.'s "I have a dream" — harkening to a patriotic American vision of democracy at work that appeared designed to appeal to lawmakers' sense of country.
Zelensky has been on a virtual world tour of western legislatures and used similar tactics in each of those speeches as well. When he addressed Britain's Parliament, he referenced both the wartime Prime Minister Winston Churchill and William Shakespeare, appealing to the United Kingdom's past to appeal for more help.
When he spoke to Canada's Parliament, he asked his audience to imagine what it would feel like to hear missile strikes at Ottawa's airport.
Zelensky has already spoken to groups of lawmakers in smaller, private settings, and is fully aware there is broader backing there for some of his asks than in the administration.
Many members of Congress have voiced support for providing Ukraine with Soviet-era fighter jets — a proposition the Biden administration has written off for now, citing logistical challenges and the potential of escalation.
In his speech, Zelensky appealed for the lawmakers to step up, aware the direct and dramatic appeal would be difficult to deny.
"In the darkest time for our country, for the whole Europe, I call on you to do more, new packages of sanctions are needed, constantly, every week until the Russian military machine stops," he said.
Zelensky has already proven to be effective at swaying American lawmakers. After a Zoom meeting earlier this month in which he appealed for help obtaining MiG fighter jets, Democrats and Republicans both rallied behind the cause — only to see it rejected a few days later by the Pentagon.
Zelensky is a relative newcomer on the political stage; he began as a comedian and television actor. A knowledge of stagecraft is critical in how he addresses the world as his country comes under siege.
A video played toward the end of his speech sought to amplify the emotion of the war, showing images of normal life in Ukraine before the war followed by the stark reality of life there now: bombings, death and fear.
It was the latest example of Zelensky using the power of recorded images to make a global appeal for help. His selfie videos walking through the streets of Kyiv have caused the world to rally around his leadership, and helped to unify a western response in punishing Russia.
Graphic images like the one in his video are rarely shown in public settings on Capitol Hill, further jolting the gathering to attention. The room was completely silent as it played.
Switching into English as he concluded his address, Zelensky punctuated an emotional appeal with words appealing to American global preeminence.
"Today it is not enough to be the leader of the nation. What it takes to be the leader of the world, being the leader of the world means to be the leader of peace," he said.
Biden's short speech could not come close to the emotional impact of Zelensky's, which the US President said he watched from the private White House residence.
But he did attempt to claim a world leader stature after Zelensky directly challenged him to step into the role.
"What's at stake here are the principles that the United States and the united nations across the world stand for," Biden said. "It's about freedom. It's about the right of people to determine their own future."
Biden underscored the brutality of what is happening on the ground, which was starkly illustrated Wednesday when a theater in Mariupol -- inside of which hundreds of people had been taking shelter -- sustained heavy damage in a bombing.
"These are atrocities," the US President said. "They're an outrage to the world."
At the same time, even Biden could not say with any certainty that the military assistance he announced to Ukraine would help bring the conflict to a swift end. Instead, he warned the fighting could persist into the future.
"I want to be honest with you," he said, "this could be a long and difficult battle."
This story has been updated with additional reporting after Biden's speech.