The Senate’s new boss. Photo: Kevin Dietsch/Getty Images As members of Congress returned to Washington this week, the focus was on Mike Johnson , who narrowly won reelection as House Speaker after initially failing on the first ballot. But in the longer run, the locus of legislative action in the second Trump administration is likely to be the U.S. Senate, where the new majority leader, John Thune , is succeeding Mitch McConnell , who served as GOP leader for a remarkable 18 years. There are