Longtime Virginia Republican strategist Boyd Marcus is switching teams to back Democratic gubernatorial nominee Terry McAuliffe, according to The Associated Press.

Marcus, who was the architect of Virginia Gov. Jim Gilmore's (R) successful 1997 campaign and has advised House Majority Leader Eric CantorEric Ivan CantorThe Hill's Morning Report — Sponsored by CVS Health — Trump’s love-hate relationship with the Senate Race for Republican Speaker rare chance to unify party for election Scalise allies upset over Ryan blindside on McCarthy endorsement MORE (R), is endorsing McAuliffe and will advise his campaign.

The longtime GOP strategist was also a top advisor to Virginia Lt. Gov. Bill Bolling (R), who planned to run for governor until it became clear Virginia Attorney General Ken Cuccinelli (R) would defeat him in a party convention. Bolling mulled a run as an independent before dropping out and has refused to give Cuccinelli his support.

The decision to back McAuliffe is a sign of a divided Virginia Republican Party. There has been plenty of tension between establishment Republicans and Tea Party conservatives who are the base of Cuccinelli's support. He and McAuliffe are locked in a tight race where each has struggled to put to bed concerns over personal financial issues.

Marcus told the AP he believes McAuliffe is better capable of working with both Democrats and Republicans.

Cuccinelli's campaign dismissed the significance of the strategist's decision. 

"Virginians are concerned about each candidate's vision for the future and how they plan to grow the economy and create jobs, not who their political consultants are," said Richard T. Cullen, a Cuccinelli spokesman.  

"Ken Cuccinelli has a long and distinguished record of leadership and service in Virginia and has laid out substantive plans that will make the Commonwealth stronger.  Terry McAuliffe, meanwhile, has been exposed as a failed job creator who has misled Virginians at every turn about his business record."

Marcus will dissolve his consulting firm and sell his shares to his partner, according to the AP.

Updated at 1:22 p.m.