Democrats are turning to Bill and Hillary Clinton — and not President Obama — to save their majority in the Senate. The Clintons have crisscrossed the country in recent weeks for Democratic candidates, and will each appear in key states this weekend where races could decide which party controls the upper chamber. While Obama has been mostly sidelined — he’ll appear at a Michigan rally on Saturday where Democrats believe a Senate seat is safely in hand — the Clintons are traveling to red states where the president is not welcome. On Saturday, Hillary Clinton will appear alongside Sen. Mary...