THE FASTER THE BETTER:

With the help of Odus Evbagharu, a political strategist Rosenthal had befriended, Rosenthal began campaigning door to door, where his biggest challenge was convincing people that the district had changed enough that a Democrat could win. "There's a perception of the suburbs that, 'Oh, it's all these white, affluent people," said Evbagharu, who is Black. "So, convincing people that this race was winnable was tough."

But where others saw obstacles, Rosenthal and Evbagharu saw opportunity. "The neighborhoods that we would send Jon to go knock doors in were predominantly Black and brown," Evbagharu said, and Rosenthal "knocked the hell out of those doors." In 2018, he ended up defeating Elkins by just more than 3 percentage points in a midterm election that was so good for Democrats they were convinced that years of Republican dominance in the state could soon be coming to an end. Rosenthal was one of 12 Democratic pick-ups in the Texas state House that year -- where Democrats across the state scored in suburban areas made more competitive.

"It was earth-shaking," said Rosenthal, now 59, who won reelection with 58 percent of the vote in November. Added Evbagharu, 30, who is now chair of the Democratic Party in Harris County, which includes Houston, "the demographics have shifted. It's helping Democrats electorally in the suburbs, and I think that's what you're going to start seeing more of."

In Rosenthal's district as it's currently drawn, the Black population -- a segment of the electorate that went overwhelmingly for Democrats in last month's midterms -- jumped to more than 21 percent, up from just 9 percent in 2000, the largest growth in suburban Black population of any U.S. county. But his district isn't the only one experiencing these demographic shifts. Suburban districts all across the country, especially in the South, are increasingly looking more like Harris County. The expanding Black population in the suburbs is dramatically changing the nation's political battlegrounds -- the neighborhoods where presidential campaigns are won or lost -- and where control of Congress will be decided for the foreseeable future.

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