State budget negotiators stripped $300 million in Metrorail funding from their spending plan this week after Gov. Robert F. McDonnell’s transportation chief made it clear that the governor would not agree to the extra money.

Construction scene at the Silver Line Metro extension near the intersection of Route 7 and Spring Hill Rd in the Tysons Corner area of McLean. (Tracy A. Woodward/The Washington Post)

It recently offered as much as $200 million toward the project, said Sen. Janet D. Howell (D-Fairfax), who has pushed for Metro’s Silver Line to Dulles International Airport.

“What is particularly galling is, the administration has been giving mixed signals,” Howell said Friday. “Two weeks ago, they indicated that they had $200 million available. Two days ago, they said they had $175 million available. And yesterday, they had zero.”

Transportation Secretary Sean T. Connaughton, who visited with negotiators Thursday to convey that there would be no money for the project, said the administration never offered that funding, but discussed it in hypothetical terms.

“In response to requests from the Senate, the Administration provided various scenarios to address issues that were raised by the Senate Democrats,” Connaughton said via e-mail. “The Administration has made consistently clear the without additional resources, the Commonwealth could not allocate additional funds to Dulles Rail or any other project. The General Assembly did not provide additional revenues and the Commonwealth’s current ability to take on additional debt is limited. In addition, the Commonwealth remains concerned with the management of the Airport Authority. Since the additional funds requested for Dulles Rail are not needed for at least two more years, there is an opportunity to revisit this issue in the future.”

The Senate’s proposed budget had included $300 million in bond money to help hold down tolls in Northern Virginia, which are due to be raised to pay for the second phase of the Silver Line. That decision could jeopardize the project, according to some, though a more broadly held view is that it will still move forward but result in heavy toll increases.

“That shows the governor and House Republicans are content to toll people to death,” said Sen. Mark Herring (D-Loudoun), who had pushed for the funding.

Herring said he had not given up hope that the money could be restored to the budget before final passage.

“I’m going to do what I can to try to turn it around,” said Herring, noting that he had called Sen. Charles Colgan (D-Prince William) to stress the importance of the project.

Colgan seems poised to give Republicans the lone Democratic vote they need in the evenly divided Senate to pass the spending plan. He has not stated definitely that he will vote for the budget, but he signed off on the budget conference report Friday.

The first phase of the $6 billion Silver Line is under construction from Falls Church to Reston and is expected to open in late 2013 or 2014. Construction on the second part of the project, which will run to Dulles International Airport and into Loudoun, is expected to start in January and be completed in five years.

To help pay for the project, tolls for a one-way trip that now cost $2.25 could increase to $4.50 as early as next year. By 2018, tolls for that one-way trip could rise to $6.75.

Herring said the decision against providing the $300 million “reveals an alarming lack of vision about economic development and transportation and it puts the project in serious jeopardy. It puts Loudoun’s participation in question and jeopardizes the whole thing.”

Bob Chase, executive director of the Northern Virginia Transportation Alliance, did not go quite that far.

“I don’t know that it kills the project,” he said. “What it does do is, it increases the likelihood that tolls will go up.”

Some Senate Republicans said they were uncomfortable with the idea of issuing bonds for toll abatement.

“It is bad policy to be going borrowing money which the state must play back with interest to do toll abatements,” Senate Majority Leader Thomas K. Norment (R-James City) said.

Sen. John Watkins (R-Powhatan), who had advocated raising the gas tax or finding other revenue sources for transportation, said the bond approach was too much for him.

Watkins also noted that the $300 million would not have been tapped in the next biennium, because a separate $150 million that the state has already committed to the project will carry them through that period.

“I understand they want to secure that [$300 million], but to sell bonds to mitigate tolls, that really is kind of a stretch,” he said. “I’d be willing to put cash into it. But to sell bonds to mitigate tolls and have to run around and have to pay interest on them, fiscally, that’s not being responsible.”