Zach Dembo, a Democrat, defeated Ralph Alvarado for a House seat in Kentucky on Tuesday. The former federal prosecutor won in the state’s Sixth District, a traditionally conservative area. This result showed Democratic strength in a place that voted heavily for President Trump two years ago, marking a major upset.

The outcome in the state's red Sixth District was a sign of Democratic strength in an area that voted heavily for President Trump two years ago.

Zach Dembo, a Democratic former federal prosecutor and Navy veteran, was elected to an open House seat in Central Kentucky's Sixth District on Tuesday, according to The Associated Press, delivering an upset in a traditionally conservative stronghold as Republicans struggled with President Trump's waning popularity.

Mr. Dembo's victory against Dr. Ralph Alvarado, a physician and former state senator who was backed by President Trump, was a signal of Democratic strength in a district that voted heavily for Mr. Trump two years ago.

The seat had been vacated by Representative Andy Barr, a Republican making a Senate bid to replace Senator Mitch McConnell, who is retiring.

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