As the state with the highest percentage of voters refusing to declare a party affiliation (more than half of voters here identify as independent), Alaska has a rich tradition of rewarding candidates who stand up to powerful figures like Mr. Trump. In the early 20th century, James Wickersham, Alaska’s congressional delegate, battled to give the territory the right to govern itself, insisting on its difference from the “Outside.” As recently as the 1990s, Gov. Wally Hickel was saying that Alaska deserved to be called its own “unique country.” And Alaska’s longtime congressman, Don Young, was so willing to stand up to the powers that be that he once held a 10-inch knife to John Boehner’s neck. (The two later became friends, and Mr. Boehner served as Mr. Young’s best man.)

The daughter of an Alaska governor, Ms. Murkowski understands this tradition better than most. She infuriated her Republican colleagues in 2017 with her vote against repealing the Affordable Care Act and rejected Mr. Trump’s nominees, voting against both Betsy DeVos as secretary of education and Brett Kavanaugh for Supreme Court justice. In that sense, she represents ideals all but lost in American political life: She may not wield a knife on the House floor, but her independent thinking and ability to consider each issue individually are relics of a time when party loyalty mattered less than your relationship with your constituents.