Dent, the leader of a group of GOP moderates, had said last year he wouldn't seek re-election. Dent has been a frequent critic of President Donald Trump and the polarization on Capitol Hill. He was facing a potentially hostile electorate in 2018.
Last month, Dent said he'd leave early, making him the third Pennsylvania Republican to resign from Congress this session. A special election to fill the final two months of Dent's term will be held Nov. 6, the day of the general election.
Dent's district was redrawn in February under court order and it's now considered a toss-up.
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