When six-term US Senator Patty Murray is up for reelection in 2028, the Washington state leader will be 78 years old. If she does not retire on her own, she may well find herself challenged by younger Democrats, as is now happening to 79-year-old Senator Ed Markey of Massachusetts. Gerontocracy is out of vogue among Democrats; many blame their party's loss of the presidency on 81-year-old Joe Biden's delay in stepping aside. If Murray forgoes the race, expect a stampede of eager Democrats hoping to succeed her. Her seat has not been vacant since 1992, so every ambitious politician in the Evergreen State will be eyeing it. Indeed, during her 2022 run for reelection, when no other big-name Democrats entered the race, Murray still drew 17 primary challengers. In Alaska that same year, when a US House seat opened for the first time in decades upon the death of Rep. Don Young, who held the office for 49 years, some 48 candidates threw their hats into the ring. Imagine how many will file if (and when) Murray steps aside. The line of Democratic contenders could resemble the throngs of hikers on the trail to Camp Muir on a summer weekend. In other words, it will practically be a mob scene. Unlike in Alaska's pioneering election system, though, platoons of candidates can be a problem in Washington - a big problem. That's because Washington's unusual top-two elections are haunted by a mathematical anomaly that could hand Murray's seat to a Republican, even in deep-blue Washington. Fortunately there are fixes, and one of them is about to debut in Seattle: unaltered top-two in general elections combined with a targeted occasional use of ranked choice voting in certain overcrowded primary elections. (For brevity, we'll call it "ranked top-two.") If the state legislature adopts this Seattle plan in 2026, it could be up and running statewide in time for the August 2028 US Senate primary. To understand ranked top-two, you need to understand the anomaly, in which top-two misfires and elects a less-popular candidate over a more-popular one. The easiest way to understand it is through the 2024 election of Dave Upthegrove, a veteran Democrat, to the state's public lands commissioner post. In that race, Upthegrove came within a hair's breadth of losing the primary, in which two Republicans and five Democrats faced off. The five Democrats gained 57 percent of the 1.9 million votes cast, but they divided their share many ways. During most of the vote-counting process, the two Republicans led, with 22 percent for Jaime Herrera Beutler and 21 percent for Sue Kuehl Pederson. Only when the final batch of ballots was tallied, days after the election, did Upthegrove's count exceed Pederson's - and by only 49 votes. Had he fallen short, the general election would have been between Republicans Beutler and Pederson, and one of them would be holding the office now. Instead, after clearing the primary, Upthegrove quickly consolidated Democrats' support and won the general with a five-point margin. A similar scenario unfolded in 2016, when three Democrats split the field for state treasurer, two Republicans advanced to the general election, and the state elected one of them, Duane Davidson. What's more, Davidson, who ended up being a one-term office holder, was the only Republican in that seat in six decades. The same thing could happen in an open US Senate race in 2028: a huge field of Democrats could hand the race to two Republicans. The Upthegrove anomaly in top-two is specific and mathematical. It's not just that both finalists are from the same party. That's normal in districts that lean red or blue. For instance, of the nine races for open congressional seats in Washington since the advent of top-two in 2008, three of them have paired two members of the same party. Most recently, in 2020, Marilyn Strickland and Beth Doglio, both Democrats, competed for the US House seat in District 10. Indeed, such same-party runoffs are a feature of top-two, not a bug...