Republican David McCormick defeated Democratic Senator Bob Casey in Pennsylvania, marking an upset that saw a former CEO of a hedge fund giant trounce a scion of a political dynasty in a year defined by appeals to the working class. McCormick’s victory effectively gives Wall Street a Senate seat ahead of major battles in Congress next year over expiring Trump-era tax cuts and extending the federal debt limit. The win also underscores how GOP’s electoral fortunes are surging in this closely...