An obscure provision in the U.S. Constitution poses a potential roadblock on Sen. Hillary Clinton’s path to becoming Secretary of State. It turns out that the Constitution (specifically Article I, Section 6) prohibits a lawmaker from taking any goverment job for which the salary was raised during the lawmaker’s elected term. As the Washington Post and numerous bloggers have noted, this would effectively preclude Clinton from taking the State Department gig. Salaries for Cabinet secretaries have been increased twice since Clinton started her second term as the junior New York senator in January 2007: to $191,300 in January 2008 and…