Sen. Frank W. Wagner (R-Virginia Beach) during a session of the Virginia Senate at the State Capitol in Richmond in February 2013 before passage of his bill changing the regulatory structure of electric utility companies. (Bob Brown/AP/ Richmond Times-Dispatch)

The Virginia governor’s race just got more crowded.

State Sen. Frank W. Wagner is running for governor in 2017, joining three other Republicans vying for their party’s nomination.

Wagner (Virginia Beach) announced that he would run the day after the state party decided it would choose its candidate in a state-run primary, which is open to all voters. That method potentially gives Wagner an edge among mainstream voters.

The alternative was a party-run convention in which activists gather to choose a nominee, a process that tends to favor more conservative candidates.

“I want all Virginians across the state to have their opportunity to choose the nominee,” said Wagner, 61. “There are a lot of Virginians that can’t come to a convention.”

Wagner said he is focused on making up ground against his opponents and raising enough money to run statewide. His candidacy was first reported by the Virginian-Pilot.

“That’s mission number one now,” he said.

Ed Gillespie, the longtime GOP strategist and former White House counselor to President George W. Bush who came close to unseating Sen. Mark R. Warner (D-Va.) in 2014, leads the field in fundraising and endorsements in his campaign for governor.

Rep. Rob Wittman (R-Va.), chairman of the House Armed Services subcommittee on readiness, and Corey A. Stewart, chairman of the Prince William Board of County Supervisors and the head of Donald Trump’s presidential campaign in Virginia, are also running for the GOP nomination.

The Democratic candidate is Lt. Gov. Ralph Northam, a pediatric neurologist from the Eastern Shore and an Army veteran who served in the state Senate before winning statewide office in 2013.

Gillespie has received endorsements from most of the Republicans in the state legislature, but on Monday, Sen. William M. Stanley Jr. (R-Franklin) announced that he is supporting Wagner.

Stanley said Wagner will focus on creating jobs in economically struggling Southwest and Southside regions, while he considers Gillespie’s focus to be on Northern Virginia.

Democratic Gov. Terry McAuliffe’s administration is an example of what happens “when we get a Washington insider as the head of our government,” Stanley said. “We need a Virginia guy. Frank’s a Virginia guy. . . . We need to elect someone far south of the Beltway who understands all of Virginia’s problems.”

Neither McAuliffe, a longtime Democratic fundraiser, nor Gillespie were born in the state, but both have lived in Northern Virginia for decades.

Gillespie and his wife, Cathy, drove the length of the state along Route 58 in the spring, campaigning along the way.

“We welcome Frank Wagner to the race, and look forward to a positive discussion about the critical issues facing Virginia, and the best conservative policy solutions that will create jobs, raise take home pay and lift people out of poverty,” Chris Leavitt, the executive director of Gillespie’s PAC, said in a statement.

Wagner said his 24 years in the General Assembly — nine in the House and 15 in the Senate — have prepared him to tackle the state’s economic challenges. McAuliffe recently announced that the state faces a $1.5 billion shortfall.

“I’ll match my résumé against any of the announced candidates, be they Democrat or Republican,” Wagner said in a phone interview.

In 2015, Wagner successfully sponsored a bill that freed Dominion Virginia Power from regular financial audits, allowing the utility to avoid giving customers refunds or reducing rates before federal rules curtailing global-warming emissions kick in.

In the state Senate, he was a primary negotiator of then-Gov. Robert F. McDonnell’s 2013 transportation funding overhaul, and he unsuccessfully pushed last year for an effective increase in regional gas taxes in Hampton Roads and Northern Virginia.

“The alternative is to borrow and build,” he said. “When you borrow and build, you’re going to take $2 out of the taxpayers’ pocket, and I think the taxpayers are wise to that.”

The Democratic Party of Virginia sought to link Wagner and Trump; Wagner said he will vote for Trump in November.

“State Senator Frank Wagner has a history of putting divisive social issues ahead of fighting for Virginians,” the Democrats’ state party executive director, Becca Slutzky, said in a statement. “Virginians need a governor who will fight for Virginians, not another Trump Republican who is out of touch with mainstream Virginia voters.”

Wagner grew up in Arlington and served five years in the Navy before building two ship-repair businesses in Hampton Roads — a vote-rich region key to both parties’ campaigns for the governor’s mansion.

He survived a challenge last year in his Republican-leaning district, which includes Virginia Beach and a small part of Norfolk. He does not have to give up his seat to run for governor.