Alaska Sen. Lisa Murkowski has won the backing of several billionaire donors in her battle for a fourth term. Leading the pack is hedge fund tycoon Ken Griffin, one of seven moguls who have donated over $25,000 to help Murkowski stay in the Senate. Griffin sent $1.5 million to Alaskans for L.I.S.A., a super PAC that can accept unlimited donations. The group, founded by former Murkowski campaign staffers, claims the acronym in its name stands for “Leadership In a Strong Alaska,” but it only backs one candidate: Murkowski, and has spent $2.7 million on her behalf. In addition to Griffin,...