But it shouldn’t bank on it. Hillary Clinton has a substantial lead in the polls over Donald Trump, and has vastly more cash on hand. But when it comes to spending that cash, her campaign may be making a strategic miscalculation. The campaign and an allied super PAC have reserved $137 million of ads across eight states — yet they’ve conspicuously left out the state that might be likeliest to tip the 2016 election: Pennsylvania. Michigan and Wisconsin were absent from the list, as well, but the Keystone State is the most curious Rust Belt omission. In May, we laid...