SHEPHERDSTOWN, W.Va. — Populist Sen. Elizabeth Warren (D-Mass.) got a rock-star reception during a standing-room-only campaign rally here Monday, as hundreds of liberal activists cheered her broadsides against corporate interests and voiced hopes that her presence might shift the political winds in an increasingly Republican state. The rally on behalf of Senate candidate Natalie Tennant was the latest in a string of recent Warren appearances in red and blue states alike, where Democratic base voters have embraced her fiery message as an envoy to working-class voters frustrated with both Wall Street and the Obama administration. “Our job is to fight...