Self-deception is powerful.
When governments foist a false scientific narrative, the results are often destructive. One such debacle occurred in the Soviet Union from mid-1920s to 1964 and was centered on a botanist, Trofim Lysenko. The modern scientific community accepted Mendelian genetics to explain inherited traits. Lysenko believed in an older view that plants and seeds could be acclimated to extreme elements, whereupon the offspring would be resistant. His ideas became the official dogma of Russian botany. With Stalin as his ally, opposing views were suppressed. Russian scientists who disagreed were ostracized, imprisoned, or executed. Lysenko destroyed Russian genetic science. The Russian people suffered many crop failures and other privations for this.