President Joe Biden’s communications staff members worry he could lose some of his political “momentum” in August while on vacation. A memo made public from political advisor Jen O’Malley Dillon and senior advisor Anita Dunn to White House chief of staff Ron Klain warned the White House must redouble its efforts to prevent an August “slump” facing the president. “For many administrations, August can be a momentum killer,” the memo warns. “For this team, August is going to be a momentum builder as we come out of last week…” Biden’s staff is eager to spin the latest spurt of legislative...