Former congresswoman Gabrielle Giffords and her husband, Mark Kelly, testified on gun-control issues before the Senate Judiciary Committee in 2013. (Nikki Kahn/THE WASHINGTON POST)

The gun-control group founded by former congresswoman Gabrielle Giffords (D-Ariz.) and her husband, Mark Kelly, is focusing its national political spending on Virginia this year, with a plan to dump $600,000 into three state Senate races.

Americans for Responsible Solutions noted that from the 2007 Virginia Tech massacre to this summer’s fatal shooting of two Roanoke broadcast journalists, the state has been uniquely affected by crimes involving firearms.

“By any measure, Virginia has experienced too much gun violence,” Hayley Zachary, the group’s executive director, said in a statement. Virginians are “demanding that candidates for office take a stand on critical policy issues which would help protect the commonwealth from future tragedies.”

The group’s PAC has paid for direct mail and online ads intended to unseat Sen. Richard H. Black (R), who has long been a lightning rod for controversy in his district that includes parts of Loudoun and Prince William counties. The PAC will also fund similar efforts to try to elect Democrats to open seats in Northern Virginia and the Richmond suburbs.

“I really don’t think the money they’re spending is going to affect any races at all,” Black said. “Virginia has a pretty comprehensive set of rules dealing with firearms, and people understand that if you’re going to have a safe community, you’re going to have citizens who have the right to keep and bear arms.”

Former congresswoman Gabrielle Giffords (D-Ariz.) urged Congress to act on gun violence during a Senate hearing on Jan. 30, 2013. Giffords was shot and injured two years ago while meeting with constituents in Tucson, Ariz. (JulieAnn McKellogg/The Washington Post)

Democrats have said that the races­ are among those that will give them the best chance to wrest control of the upper chamber from Republicans, who have a two-seat majority. One vote separates the parties because Lt. Gov. Ralph Northam (D) is the tiebreaker.

This year’s expenditure matches­ the amount the group spent in 2013 to help elect Democratic Gov. Terry McAuliffe and Attorney General Mark R. Herring, who were embroiled in two of the most contentious political contests in the country that year.

Since then, the Republicans’ ­veto-proof majority in the House of Delegates has blocked much of McAuliffe’s agenda, including Medicaid expansion, nonpartisan redistricting and stricter gun laws.

While campaigning for governor, McAuliffe scrapped the theory that Democrats running statewide in the once-reliably red state had to tread lightly on Second Amendment issues. Instead, he pushed for gun control and other liberal causes that endeared him to liberal and moderate voters in the Washington suburbs.

McAuliffe wants to require background checks for private transactions at gun shows and prohibit gun possession by people convicted of domestic violence and stalking misdemeanors. He would ban anyone subject to a protection-from-abuse order from having a gun, and has also tried to reinstate Virginia’s one-a-month limit on handgun purchases.

Republicans have said efforts to further regulate gun transactions and ownership won’t stop criminals determined to do harm. They also say more should be done to identify and treat mentally ill individuals at risk for committing violent crimes.

Some Democrats believe gaining control of the Senate is the first step in a long-term strategy to control the legislature. They are banking on a scenario in which the outcome of a lawsuit challenging the boundaries of a dozen House districts makes a slew of reliably Republican districts competitive.

But that could be a long way off. For now, all eyes will be on the Senate races this fall.

In Northern Virginia, Black, a former Marine combat pilot and lawyer, faces a challenge from pediatrician Jill McCabe. As one of the most conservative members of the legislature, Black is also a top target of Emily’s List, which backs Democratic women who support abortion rights.

In a nearby district that spans Prince William County, Manassas City and Manassas Park City, Republican Harry J. “Hal” Parrish II, who is mayor of Manassas, and Democrat Jeremy McPike, who works for the city of Alexandria, are vying for the seat of retiring Sen. Charles J. Colgan (D-Prince William).

Asked to lay out Parrish’s platform on guns, his campaign manager, Luisa Guerra, said the issue doesn’t resonate with voters in the district as strongly as transportation, education and jobs do.

In a swing district that includes Richmond and the surrounding area, Democrat Dan Gecker, a Chesterfield County supervisor, faces Republican Glen Sturtevant, a Richmond School Board member, in the race to succeed retiring Sen. John C. Watkins (R-Powhatan).

Zachary, the Americans for Responsible Solutions official, said: “Some vying for office this fall want to protect the loopholes in Virginia law that let domestic abusers, convicted felons, and the dangerously mentally ill buy guns without a background check.”

In response, Sturtevant’s campaign manager, Matthew Brown, said his candidate favors treatment of the state’s mentally ill to strengthening gun laws.

“Glen believes we must strongly and vigorously enforce Virginia’s existing gun laws to ensure those who are ineligible cannot possess a firearm, [and] support local and state police in their efforts to keep our communities safe,” he said.

The gun-control group acknowledged that attackers responsible for some tragedies, such as last week’s shooting in Oregon that left nine dead, obtained their firearms legally. But, Zachary said, background checks for all gun sales would “make our communities safer while respecting the rights of responsible, law-abiding gun owners.”

Giffords was seriously wounded in a 2011 shooting during a constituent meeting in Tucson that killed six people.