There’s little question Michigan’s U.S. Senate race is a bellwether for the entire nation in this midterm election. The contest between Republican Mike Rogers and Democrat Abdul El-Sayed is now the most expensive election in Michigan history, with $400 million, perhaps $500 million by Tuesday, in spending. But how did Michigan’s open U.S. Senate seat become such a marquee race? And how did El-Sayed, whose progressive policies were considered far outside the mainstream just eight years ago, become a leading contender for the U.S. Senate? The answer is that Michigan has been moving left for a decade. El-Sayed didn’t necessarily change his politics to win Michigan. Michigan’s political environment changed enough to make his politics more popular. To understand how, we have to start in 2016. In the bitter presidential rivalry that year, Vermont Sen. Bernie Sanders beat Democratic establishment darling Hillary Clinton in Michigan’s primary by more than 17,000 votes. That victory laid the groundwork for a candidate like El-Sayed. Sanders’ popularity didn’t translate into the Democ