Washington’s chattering classes are aghast that Exxon Mobil CEO Rex Tillerson is reportedly the leading choice to be President-elect Trump’s secretary of state. Having worked at both Exxon Mobil and the State Department, I’d suggest that these objections say more about D.C. insularity than about Mr. Tillerson’s suitability for the post. Specifically, they reflect political intellectuals’ unfamiliarity with—and more than a hint of underlying contempt toward—America’s traditional private sector.

It’s not that politicians and...