Republican Rick Saccone conceded defeat on Wednesday night to Democrat Conor Lamb in a Pennsylvania special congressional election.

The 33-year-old Lamb, backed by his district's influential labor unions, beat Saccone by around 750 votes in a deeply Republican district that President Trump won by nearly 20 percentage points in the 2016 election. Saccone, a state lawmaker, had one of the most conservative voting records in the state legislature. 

In the race, Lamb downplayed opposition to Trump, who remains more popular in the district than nationally. He opposed sweeping new gun regulations and supported Trump's steel tariffs, but he is a fierce critic of Republicans' tax cuts and their economic and health care policies. -NBC

Saccone, meanwhile, embraced Trump - who offered ample support for the Republican over twitter, and appeared at a headline-generating rally the Saturday before the election. 

Lamb will succeed Republican Tim Murphy, and eight-term congressman who resigned in October while embroiled in a sex scandal.

Republicans mulled a recount and legal action over the Lamb's razor thin lead, however the Democrat's margin over Saccone, 60, continued to increase as officials continued to count votes. Outside Republican groups spent approximately $10 million on Lamb - around seven times as much as similar groups spent on Lamb's endorsement.