Betting against Tom Cotton has become a dicey proposition. In 2020, the Arkansas senator suggested the eminently reasonable possibility that perhaps the coronavirus originating in Wuhan, China, was the result of a leak from a local laboratory that experimented with precisely such infectious material. The Washington Post’s “fact-checker” sneered, echoing many in his industry, “Tom Cotton keeps repeating a coronavirus conspiracy theory that was already debunked.” Once it became clear that Cotton’s contention was certainly plausible and entirely rational based on the evidence, the Post admitted it was neither a “conspiracy theory” nor “debunked,” and had never been either of those two things. In 2021, Democrats defeated a Republican amendment to the stimulus bill, the result of which, Cotton said, would mean incarcerated individuals such as the Boston bomber, Dzhokhar Tsarnaev, would receive a check...