Democratic candidates for Virginia lieutenant governor Gene Rossi, left, Susan Platt and Justin Fairfax. (Rossi, Platt, Fairfax campaigns)

All three Democratic candidates for Virginia lieutenant governor have pledged not to take campaign contributions from utility giant Dominion Energy, another sign of how some politicians are distancing themselves from the state’s largest political donor.

The Democrats — former federal prosecutors Justin Fairfax and Gene Rossi and lobbyist Susan Platt — said Tuesday night that they were also skeptical about two planned natural-gas pipelines, one of which is a Dominion project and major priority for the utility.

Dominion’s proposed pipeline would run 600 miles from West Virginia through Virginia to North Carolina. While final approval of the project lies with federal regulators, state environmental officials appointed by the governor can deny permits for the project if they determine it would violate clean-water protections.

“We have to put more emphasis on solar . . . and alternative sources of energy,” Rossi said. Like his rivals, he would not go as far as refusing money from the state party or other organizations that accept Dominion cash.

Dominion’s role in politics came up at a lieutenant-governor candidate forum Tuesday at George Mason University, hosted by the university’s Schar School of Policy and Government and the Northern Virginia Chamber of Commerce. The forum featured the three Democrats and three Republicans running for their party’s nominations.

The Republican candidates for lieutenant governor in Virginia: State Sen. Bryce E. Reeves (Spotsylvania), left; Del. Glenn R. Davis Jr. (Virginia Beach); and state Sen. Jill Holtzman Vogel (Fauquier). (From left: Reeves campaign; Timothy C. Wright for The Washington Post; Bob Brown/Richmond Times-Dispatch via AP)

The candidates for the GOP nomination — Del. Glenn R. Davis Jr. (Virginia Beach) and state Sens. Bryce E. Reeves (Spotsylvania) and Jill Holtzman Vogel (Fauquier) — have all taken money from Dominion in the past. They said it is up to voters to decide whether a source of campaign financing is problematic.

“Some people who want to participate in the political process want to engage in the issues by standing outside and yelling,” said Vogel, a campaign finance attorney for conservative groups. “Other people are going to decide they are going to make a contribution.”

The role of Dominion in state politics and pipelines has emerged as an issue in the 2017 election cycle.

Dozens of Democratic candidates running for delegate seats have pledged not to take money from Dominion, which has made $15 million in political contributions in Virginia over the past two decades, giving about equally to Republicans and Democrats, according to the Virginia Public Access Project.

Democratic gubernatorial candidate Tom Perriello is critical of the company’s dominance over Virginia’s energy sector and has made opposition to its gas pipeline project central to his campaign.

Perriello’s rival for the nomination, Lt. Gov. Ralph Northam, has accepted Dominion cash and holds stock in the company. He has repeatedly refused to say whether he opposes or supports the pipeline but has emphasized that the project needs to meet strict environmental standards. Attorney General Mark Herring (D), who is seeking a second term, has also accepted contributions from the energy company.

Dominion has defended its right to participate in politics. The company’s chief executive recently sent a letter to 76,000 employees, retirees and shareholders reminding them the importance of the pipeline to the company’s future and urging them to evaluate candidates’ positions on the subject.

The job of lieutenant governor is limited: He or she presides over the state Senate and breaks tie votes, and fills in if the governor is incapacitated. In practice, the office serves as a launchpad to run for governor.

Across party lines, candidates at Tuesday’s forum were skeptical about imposing a 1 percent sales tax in the D.C. region to provide a dedicated source of funding for Metro. Republicans said they preferred finding money elsewhere in the state or Washington Metropolitan Area Transit Authority budgets.

“It’s amazing the first thing anybody wants to do is start raising taxes,” Reeves said. “A lot of organizations have a lot of fat and are unwilling to show you where that fat is inside your budget.”

The Democrats said they want a dedicated source of revenue but stopped short of supporting the tax. They said the federal government should provide more funding.

Democrats and Republicans alike were cool to repealing Virginia’s “right to work” law barring compulsory union membership, as Perriello recently championed. The GOP field said the law was crucial to Virginia’s economic competitiveness, while the Democrats had little appetite to take on repeal even though they support unions.

“I would support [repeal], but I’m also a realist,” Fairfax said. “It’s not something we need to fight for right now.”

The realities of Virginia’s political environment did not stop the Democratic candidates from supporting other policies opposed by the Republican-controlled legislature, including a $15 minimum wage and expansion of Medicaid to low-income Virginia residents.

Democrats also lobbed a few shots at President Trump, who polls show is unpopular in Virginia, while Republicans never mentioned him by name.

“He came out with this budget, I suspect, to distract us from the Russia investigation,” Platt said. “He’s cutting Meals on Wheels, student health insurance programs and student loan programs.”

The Republican candidates agreed that they want to overhaul the state tax code, block the expansion of Medicaid to low-income Virginians and reduce regulations.

The only policy difference came on the thorny question of setting a floor for the regional gas tax in Northern Virginia and Hampton Roads. It was not included in a 2013 deal to raise transportation revenue but continues to be pushed by local community leaders who say they need a minimum tax level to fund transit and road projects to address congestion.

Vogel and Reeves, tax-averse conservatives who voted against the 2013 deal in the state Senate, doubted whether such a maneuver was politically feasible. But Davis said more-reliable sources of tax revenue would protect taxpayers from higher borrowing costs for the road projects.

“This is a protective measure,” Davis said. “This isn’t a tax-increase guarantee.”

Asked how they would work with a Democratic governor, the three Republicans touted instances when they had worked across party lines to pass legislation.

The primaries are June 13.