Presides over the Supreme Court since 2005 after nomination by a Republican president, serving as the Court’s administrative leader and directing opinion assignments under the judicial authority of Article III. Known for a conservative yet institution-preserving approach that favors narrow, precedent-based rulings—most notably writing the opinion upholding the Affordable Care Act’s individual mandate in 2012 and joining the majority that invalidated Section 4 of the Voting Rights Act in 2013—shaping modern doctrine on federal power and court legitimacy.