On the day the Russian army invaded Ukraine, Volodymyr Zelenskyy met withSean Penn.

Of course he did.

“你的眼睛只是看着勇气,”Penn says to his film crew as they exit the meeting room of the Ukrainian president in the actor’s latest documentary, “Superpower.”

Undoubtedly, Zelenskyy had better things to do on the first day of a war. But as a former comedian and actor, he knows the power of PR and celebrity, and to Penn’s surprise, the president kept the appointment that was made before anyone knew that day — Feb. 24, 2022 — would be the start of the conflict.

“Superpower,” which Penn co-directed with Aaron Kaufman, debuts on Paramount+ on Monday, Sept. 18, arriving at a time when the war, started byRussian President Vladimir Putin, is grinding toward another cold winter. Ukraine is considered by many experts to be “winning,” but its counteroffensive to retake occupied land is going slow.

It is universally agreed upon that to win, Ukraine will need more advanced weaponry from the West, and “Superpower” is a direct plea for that to happen — a rallying cry for Americans to step up for the cause at a time when polls show support is slipping.

“We’re going to miss opportunities to make this a short war,” Alexander Vindman, the former director for European affairs for the U.S. National Security Council and a key figure in then-President Trump’s first impeachment, tells Penn, “and risk more of a confrontation with Russia the longer it goes on.”

或者,正如Rep. Eric Swalwell, D-Castro Valley, tells Penn, “If you want to keep China out of Taiwan, keep Ukraine in the fight. … If Ukraine loses, we lose.”

Others interviewed include Mateusz Morawiecki, prime minister of neighboring Poland; Steven Pifer, former U.S. ambassador to Ukraine; and Vitali Klitschko, mayor of Kyiv and a former heavyweight boxing champion. Penn also talks to regular Ukrainian citizens, war widows and soldiers — he made seven trips to the country to make the film — and visits the front lines.

Penn says he is a curious person, and frankly admits to using his celebrity to gain access to some of the world’s trouble spots. He formed a charity organization andspent months on the ground in Haitiafter the country’s devastating earthquake in 2010,notoriously interviewedthe Mexican drug lord known as “El Chapo,” and acted as a freelance journalist in the Middle East during the War on Terror (hereported for the Chroniclefrom Iran in 2005).

“Superpower,” one of severaldocumentaries about the war in Ukraine, doesn’t break any news, but Penn, atwo-time Oscar-winning actoranddirector of several feature films, is a skilled storyteller. He and Kaufman do an excellent job of providing a contextual overview of the conflict, from its origins — the trajectory of both Russia and Ukraine in the post-Soviet era — to its political stakes, the mood of the Ukrainian people and the fascinating man who is leading them.

Penn, whose liberal politics are well known, also issues a plea to Americans for unity. In the film, he goes onSean Hannity’s show在福克斯新闻为乌克兰和juxtaposes pictures of perhaps the two most polarizing members of Congress,Alexandria Ocasio-Cortezand Marjorie Taylor Greene. Penn’s voice-over: “If we don’t find common cause, we’ll kill each other.”

There is a funny moment in “Superpower,” or at least a weird one, when Penn talks of the time he once met Putin. It was in 2001 when the director was at the Moscow Film Festival withJack Nicholsonto promote their film “The Pledge.” There is a picture of Penn on the left, Putin on the right and Nicholson in the middle, smiling that Jack Nicholson smile.

Penn doesn’t say what was discussed, only commenting, “that night has become a deviant memory.”

Reach G. Allen Johnson:ajohnson@sfchronicle.com