Valadao's defeat also means that of the 25 House Republicans who had won in 2016 in a district where Hillary Clinton had won more votes than Donald Trump, 22 of those seats went for a Democrat in the 2018 mid terms.
Of those 25 seats, the only GOP survivors were Rep. John Katko in New York, Rep. Brian Fitzpatrick in Pennsylvania, and Rep. Will Hurd in Texas.
Those setbacks were a prime reason why the GOP lost its majority in the House, as Democrats will take charge with at least 235 seats in the 116th Congress.
There is one undecided U.S. House seat left, North Carolina's 9th district, which was originally called for Republicans, but has been consumed by allegations of absentee ballot fraud, as the Democrat in race on Thursday withdrew his concession.
"Today I withdraw my concession and call on Mark Harris to end his silence and tell us exactly what he knew, and when," said Democrat Dan McCready.
Democrats on Thursday again made clear they would object to Harris being seated from North Carolina, and also raised the possibility that an objection would be made to Republican Rep. Ross Spano of Florida, who admitted in the last week that he broke federal election laws by taking $180,000 in loans during the campaign, and funneling most of the money into his campaign, by designating it as 'personal funds.'
"The issue in Florida is one that we're tracking as well," said House Democratic Leader Nancy Pelosi, who said the issues at hand are serious.
"This is about undermining the integrity of our elections," Pelosi told reporters at the Capitol.