I wonder if there'll come a time when the editor of National Review circa 2038 wonders when it was, exactly, that the decision was made to make robust enthusiasm about torture a defining value of the American conservative movement.
I don't know why Yglesias treats torture as a strange belief for conservatives. It actually has a lot of roots in conservative culture. If the "freedom of authority" in relation to criminals is not the most important meaning of American freedom for conservatives, it's certainly close. That's one of the reasons why figures like John Wayne and movies like High Noon and the Dirty Harry series have iconic status among the right. That stress on the freedom for authority dovetailed with conservative racism became especially important for conservatives after the emergence of the Civil Rights Movement and the race riots of the Sixties. Once the rights of blacks were recognized, conservatives believed that blacks needed to be more closely supervised than ever.
As the racism of the right has been extended from African-Americans to Muslims, the appeal of authoritarian abuses like waterboarding, sensory deprivation, and other forms of torture has also grown.
Support for torture also fits well with conservative masculinity. As most recently evidenced in Rudy Giuliani's campaign persona, conservative masculinity puts a lot of emphasis on breaking the rules on telling the truth, corruption, and the like. Just as killing somebody used to be an initiation right for Mafia members, defying rules has become a test of right-wing manhood. In the case of defying the rules governing interrogation, conservatives get a special kick out of flouting various kinds of "liberal" laws and regulations. In this sense, supporting torture is a way to oppose liberalism as well.
Conservative support for torture is a kind of self-isolating gesture. Conservatives are deeply disappointed in American society for its lack of support for the Iraq War in particular and lack of support for the conservative political agenda in general. From the right-wing point of view, American society just isn't good enough, moral enough, or tough enough for conservatism. Supporting is a way for conservatives to feel morally superior as they isolate themselves from the moral sense of the anti-conservative majority in the United States.
Supporting torture is a way for conservatives to give the finger to American society in general. Given the obscene character of torture practices like waterboarding, conservative support for torture works well as an obscene gesture.