From left, Democratic Virginia Reps. Don Beyer, Robert C. “Bobby” Scott and Gerald E. Connolly celebrate their victories on Nov. 8 in Falls Church, Va. ( John McDonnell / The Washington Post )

Democratic candidate for governor Ralph Northam has the support of Democrats in the Virginia congressional delegation — except for one.

Rep. Gerald E. Connolly confirmed Friday night that he will remain neutral out of deference to Tom Perriello, the former one-term congressman whose late entry into the race scrambled the nominating contest.

“Tom Perriello and I were colleagues in Congress and remain friends to this day,” Connolly said in a statement. “While I continue to believe that Ralph Northam is a great leader and fighter for progressive values, I welcome Tom’s entrance to the race and believe both candidates have much to gain from a vigorous contest.”

Connolly made the statement after Northam’s campaign trumpeted the endorsements of Sens. Mark R. Warner and Tim Kaine and Reps. Robert C. “Bobby” Scott, Don Beyer and A. Donald McEachin.

Before Perriello announced his candidacy Thursday, Northam appeared to have a clear path to the nomination, saving himself the effort and expense of a contested primary.

He had already wrapped up the support of Gov. Terry McAuliffe (D) and Attorney General Mark R. Herring (D), and Democrats in the state legislature were on board.

Connolly, a five-term congressman and former chairman of the Fairfax County Board of Supervisors, is the state party’s most prominent elected official to withhold his endorsement.

He represents a heavily Democratic slice of Northern Virginia, spanning most of Fairfax and Prince William counties, where Northam and Perriello will probably campaign.

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Northam is lieutenant governor and previously served in the state Senate. A native of the Eastern Shore, he is a pediatric neurologist and Army veteran.

Perriello grew up in Charlottesville and was swept into Congress in 2009. After losing his seat, Perriello worked for a liberal think tank and the State Department.

Republicans seeking the nomination include former GOP strategist Ed Gillespie; Corey A. Stewart, chairman of the Prince William Board of County Supervisors; state Sen. Frank W. Wagner (Virginia Beach); and businessman Denver Riggleman.

Both parties hold their primaries in June.