legal assistance treaty with Ukraine and "was following the law to the letter when it comes to unearthing the long-standing corruption that has swirled in Ukraine and allegedly involves powerful Democrats like Joe Biden." Alleging false flag attacks Limbaugh claimed that the October 2018 United States mail bombing attempts were perpetuated as a false flag operation to draw public attention away from Central American migrant caravans. He reiterated these claims two weeks after the arrest of the primary suspect Cesar Sayoc, a registered Republican. On his show, Limbaugh said that the Christchurch mosque shootings of March 2019 may have been a false-flag operation. Limbaugh described "an ongoing theory" that the shooter was actually "a leftist" trying to smear the right. Despite providing no source or evidence, Limbaugh continued: "you can't immediately discount this. The left is this insane, they are this crazy." Controversies and inaccuracies Comedian Al Franken, who later became a Senator, wrote a satirical 1996 book, Rush Limbaugh Is a Big Fat Idiot and Other Observations, in which he accused Limbaugh of distorting facts to serve his own political biases. Of Limbaugh's controversial statements and allegations they have investigated, Politifact has rated 84% as ranging from "Mostly False" to "Pants On Fire" (signifying false statements that cannot be reasonably assessed as merely errors), with 5% of Limbaugh's contested statements rising to the level of "Mostly True" and 0% rated "True". These debunked allegations by Limbaugh include suggestions that the existence of gorillas disproves the theory of evolution, that Ted Kennedy sent a letter to Soviet General Secretary Yuri Andropov seeking to undercut President Reagan, that a recent lack of hurricanes disproves climate change, and that President Obama wanted to mandate circumcision. Scientific fact Limbaugh has been criticized for inaccuracies by the Environmental Defense Fund. A defense fund report authored by Princeton University endowed geoscience professor Michael Oppenheimer and professor of biology David Wilcove lists 14 significant scientific facts that, the authors allege, Limbaugh misrepresented in his book The Way Things Ought to Be. The authors conclude that "Rush Limbaugh ... allows his political bias to distort the truth about a whole range of important scientific issues." Hu Jintao Limbaugh was heavily criticized for mocking Hu Jintao, then the General Secretary of the Chinese Communist Party and paramount leader of the People's Republic of China, and the Chinese language during an episode. After proceeding to label Hu as a