Virginia Gov. Bob McDonnell and his predecessor, Democratic U.S. Senate candidate Tim Kaine, attempted to affix blame Tuesday for looming high tolls around Washington Dulles International Airport as the fallout from last week's budget showdown seeped into the state's high-profile Senate race.

McDonnell defended his part in thwarting attempts to add up to $300 million in the budget for the new Metro Silver Line to the Dulles corridor and beyond. Democrats insisted the money was necessary to lower the cost of tolls in the region, which are scheduled to balloon in coming years.

The Republican governor tried to steer blame toward Kaine, who was at the helm in 2006 when the state announced plans to turn over the Dulles tolls to the Metropolitan Washington Airports Authority to help pay for the project.

McDonnell has backed Kaine's likely opponent, former Republican Gov. George Allen, in the race for Virginia's open Senate seat.

Kaine handed responsibility for the tolls to MWAA with "no caps on tolls, no money for the Silver Line for Phase Two," McDonnell said Tuesday on WTOP's monthly "Ask the Governor" program. "Fast-forward three years, and I haven't heard a word since I've been governor about the need for more money [until now]."

That sparked a strong response from Kaine's campaign.

"The anti-investment mentality in Richmond and Washington that threatens funding for this and other projects is bad for Virginia's economy and businesses," Kaine spokeswoman Brandi Hoffine said. "Gov. Kaine continues to believe that additional statewide revenues are necessary to keep Phase Two of this important project on track and ensure that Northern Virginia residents don't pay excessive tolls."

McDonnell last week convinced state Sen. Chuck Colgan, a Manassas Democrat, to vote for the budget, ending a stalemate surrounding Dulles' future.

Democrats accused McDonnell of revising history to wash his hands of the politically poisonous rising tolls. At the time, Kaine's plan to give MWAA oversight of the tolls had bipartisan support from Virginia's congressional delegation, including then-U.S. Sen. Allen.

The federal government set aside $900 million for the first half of the project in the deal cut by Kaine, but there was an understanding that the state and localities were on their own for the second phase, said Bob Chase, president of the Northern Virginia Transportation Alliance. "Virginia hasn't really put anything close to its fair share into this project," Chase said.