Virginia state Sen. R. Edward Houck conceded defeat Thursday, dashing any Democratic hopes of hanging on to power in Richmond.

The Spotsylvania Democrat announced his decision on Facebook and at a news conference in Fredericksburg after Republican Bryce Reeves picked up four more votes Thursday in Louisa County.

Reeves’s victory over the 28-year Senate veteran delivers the last bastion of Democratic power in Richmond into the hands of the GOP, which already controlled the House, the governor’s mansion and the attorney general’s office.

Republicans have not held such sway in Richmond since the Civil War.

Houck suggested the results will be dire.

“We were the backstop to a lot of social conservative legislation that we felt like, and I feel like, was not quite good for Virginia,” he told reporters in a conference call. “It will be interesting to see if that type of legislation is now embraced by a Republican-controlled Senate. I would suspect it will be.”

That prediction — echoed in a Planned Parenthood Advocates of Virginia news release warning of “alarming repercussions” — came after Houck conceded in a phone call to Reeves.

“We had a long conversation discussing the campaign, and he offered some very uplifting advice to help me during this transition,” Reeves said in a news release. “I appreciate his message about the importance of a supportive family, and the work that you as supporters have done. I want to thank him for his friendly advice and his service to the district these past 28 years.”

Republicans captured the Senate with campaigns that took a page out of Gov. Robert F. McDonnell’s playbook, steering clear of hot-button social issues in favor of jobs, traffic and education.

The strategy allowed them to pick up two seats in the 40-seat Senate, creating an even 20-20 split between Republicans and Democrats. Because a Republican, Lt. Gov. Bill Bolling, will break any tie votes, Republicans expect that to put them in control. Democrats would prefer a power-sharing agreement like the one hatched the only other time the Senate was evenly divided, in the 1990s. But Republicans have signaled they are not inclined to share.

“I am looking forward to serving the people of the 17th District and working with Governor Bob McDonnell in Richmond to create jobs, grow our economy, improve our schools and keep Virginia moving in the right direction,” Reeves said.

On election night, the race seemed destined for a recount, with Reeves leading by just 86 votes. His lead widened to more than 200 on Wednesday after a “keying error” discovered in Culpeper. Come Thursday, Houck’s only hope was Louisa County, the only jurisdiction that had not completed its post-election review.

The county had to count eight provisional ballots and review records for an entire precinct where 535 ballots had been cast. Three of the eight provisional ballots were counted, and they all went for Reeves. The rest were never opened, because they were cast by unregistered voters, elections officials said.

A fourth vote for Reeves was on a paper ballot that turned up in an envelope where it was mistakenly placed on Election Day, said Jack Manzari, chairman of Louisa’s electoral board. That vote was cast by someone who was prevented by physical disability from coming inside the polling place. A poll worker took a paper ballot to the parking lot so the person could vote there.

That ballot had not been placed in the proper envelope, but elections officials discovered it Thursday afternoon during their normal, post-election review.

Because the vote was so close, Houck could have requested a recount. Friends and supporters had encouraged him to do so, but Houck said he did not think he could overcome Reeves’s lead once it grew beyond 200.

“This would be creating false hope,” he said. “I would rather square up with my supporters, the people of this district, the commonwealth of Virginia, the Senate of Virginia. I’d rather go ahead and say, ‘Look, it’s over. It’s done.’ ”