Terry McAuliffe, the Democratic candidate for governor in Virginia, lashed out Friday at Republican Attorney General Ken Cuccinelli for threatening to use his office to block the historic transportation package that passed the General Assembly last month.

During a sitdown Thursday with Politico at the Conservative Political Action Conference, Cuccinelli hinted that he may yet issue a legal opinion that could derail the tax hike in the package that would raise the extra money the state needs. The measure is awaiting Gov. Bob McDonnell's signature.

The fragile compromise to raise $3.5 billion for roadwork over the next five years nearly fell apart at the last minute when Cuccinelli raised constitutional concerns after repeatedly bashing the package as an "enormous tax hike."

McAuliffe, who personally called Democratic lawmakers late in the session to help get the bill passed, criticized Cuccinelli for meddling. Cuccinelli's legal opinions can't on their own take down the transportation bill, but as the state's top lawyer his legal expertise weighs heavily on lawmakers wary of losing court fights over new laws.

"His decision to torpedo a historic mainstream compromise on transportation would reflect a disturbing trend of using his taxpayer-funded office to advance his own ideological agenda," McAuliffe said. "I urge the Attorney General to state unequivocally that he will not use his office to derail the mainstream compromise reached by the legislature and Gov. McDonnell. Addressing Virginia's transportation challenges is too important for one candidate's ideological agenda to imperil this bipartisan compromise."

Cuccinelli was CPAC's first speaker at its Thursday opening. He used the national soapbox to lay out a five-point agenda for his campaign, but made no mention of transportation in his 18-minute speech. His campaign has said that he will introduce his own plan to fix Virginia's roads and highways later in the campaign.

"Perhaps McAuliffe can arrange a private screening of Schoolhouse Rock to understand that the legislation isn't final until the governor signs the bill," Cuccinelli spokeswoman Anna Nix said.