Republican Rep. Barbara Cubin is a known commodity in Wyoming, which has fewer people than any other state and an electorate in which Republican registrants outnumber Democrats by a 2-to-1 ratio. Yet Cubin — who first won for Congress in 1994 — is not the most popular Republican to have held Wyoming’s only House seat, which previously was held by current two-term Sen. Craig Thomas and incumbent Vice President Dick Cheney. While the GOP ticket of President Bush and Cheney was sopping up 69 percent of the Wyoming vote in 2004, Cubin was elected to a seventh term with 55...