"a practical necessity and moral imperative that those who have received much should be obligated to pay ... in the same proportion". On January 25, 2013, King published an essay titled "Guns" via Amazon.com's Kindle single feature, which discusses the gun debate in the wake of the Sandy Hook Elementary School shooting. King called for gun owners to support a ban on automatic and semi-automatic weapons, writing, "Autos and semi-autos are weapons of mass destruction...When lunatics want to make war on the unarmed and unprepared, these are the weapons they use." The essay became the fifth-bestselling non-fiction title for the Kindle. King has criticized Donald Trump and Rep. Steve King, deeming them racists. In June 2018, King called for the release of the Ukrainian filmmaker Oleg Sentsov, who was jailed in Russia. In the 2020 Democratic Party presidential primaries, King endorsed Elizabeth Warren's campaign. Warren eventually suspended her campaign, and King later endorsed Joe Biden's campaign in the 2020 general election. In 2022, during the Russian invasion of Ukraine, King expressed support for Ukraine. On his Twitter account, King posted a photo in an "I stand with Ukraine" t-shirt and later tweeted that he refuses to cooperate with Russian publishers. In July 2022, Stephen King appeared in a video call with the Russian pranksters Vovan and Lexus who played the role of Volodymyr Zelenskyy. In the call Stephen King said "You can always find things about people to pull them down. Washington and Jefferson were slave owners — that doesn't mean they didn't do many good things to the United States of America. There are always people who have flaws, we are humans. On the whole, I think Bandera is a great man, and you're a great man, and Viva Ukraine!" However, King later realized that he was pranked and apologized on Twitter, noting that he wasn't the only victim and "other victims who fell for these guys include J.K. Rowling, Prince Harry, and Justin Trudeau". King testified in an August 2022 in a case brought by the U.S. Justice Department to block a $2.2 billion merger of Penguin Random House and Simon & Schuster (two of the "Big Five" book publishers). The New York Times credited King's high-profile testimony, which was against his own publisher, with helping to convince presiding judge Florence Y. Pan with ultimately blocking the merger. Maine politics King endorsed Shenna Bellows in the 2014 U.S.