In Michigan, a Suburban County That Flipped Blue Isn’t Looking Back

“They told me, ‘That’s cute, you’re going to get destroyed,’” said Ms. McMorrow, who was seeking to challenge the seat of State Senator Marty Knollenberg, a Republican. “That was kind of the attitude. Nobody took it seriously at all.”

But 2018 proved that the blue shift was here to stay.

Ms. McMorrow won her race for State Senate. And a number of other seats also flipped from red to blue: two more in the State House and two congressional seats in Oakland County. Democrats took a slim majority in the County Board of Commissioners for the first time ever. And of course, the state’s governor, Gretchen Whitmer, a Democrat, won the county by a margin of 17 points that year. The county also helped elect Dana Nessel as state attorney general and Jocelyn Benson as secretary of state, flipping those seats from red to blue.

The shift was partly driven by demographics. A county that was 93 percent white in 1980 was only 75 percent white by 2019. Coupled with that, Mr. Patterson’s goal of turning Oakland County into “Automation Alley,” a landing spot for high tech businesses tied to the automotive industry, lured diverse and highly educated young people with good-paying jobs who in turn, brought their politics.

“There were a lot of the unintended consequences of Automation Alley,” Mr. Alexander said of Mr. Patterson’s push, which began in the 1990s. “Those tech people moved in and they were younger and more liberal individuals.”

In 2019, with a first 11-to-10 majority on the Board of Commissioners, Democrats had the power to name a successor to Mr. Patterson when he died that year at the age of 80. They appointed Mr. Coulter, who is now running for the seat in 2020 against the Republican, Mike Kowall, a former state legislator from White Lake Township in western Oakland County.

Now, 2020 is looking to be an even bluer year for Democrats in Oakland County. Mr. Coulter’s internal polls show him and Joseph R. Biden Jr. ahead by more than 20 points there. Republicans’ internal polling also shows double-digit, albeit somewhat smaller, margins.

A New York Times/Sienna poll of Michigan taken from Oct. 23-26 shows Mr. Biden with an eight-point lead over Mr. Trump. The loss of Michigan would not be a fatal blow for Mr. Trump, who won the state in 2016 by a margin of 10,704 votes, but it is one of the three states, along with Wisconsin and Pennsylvania, that flipped from blue to red in 2016 and gave him the electoral votes he needed to win the White House. Mr. Biden has been holding on to a consistent lead in all three states since this summer.