Senate Minority Leader Mitch McConnell operates with a steely resolve, a political discipline that leaves nothing to chance. A childhood bout with polio instilled in him an enormous capacity for patience. And for 25 years in Congress, the Kentucky Republican has waited for the moment now before him: the chance to become Senate majority leader. With four seats needed to flip the chamber, or three if a Republican is elected president (because the vice president could break a tie), the GOP has its best opportunity in years to gain full control of Congress. But McConnell and his party must first...
