VIRGINIA IS one of four states facing legislative elections this fall, and the only one where control of both chambers, each run by Republicans holding tissue-thin margins, hangs in the balance. Small wonder, then, to see one of the most vulnerable Republicans, now clinging to a seat in Northern Virginia, struggling to do damage control on a key issue: guns.

The state has suffered its share of firearms-induced carnage: 32 people massacred in 2007 by a gunman on the campus of Virginia Tech; an additional dozen killed this May by a shooter at a municipal building in Virginia Beach. Neither trauma dented state Republicans’ determination to block even the most popular gun safety measures or rescind sensible ones already on the books.

In 2012, the General Assembly, led by Republicans, repealed a 20-year-old law limiting handgun purchases to one a month. And while a 2017 pollshowed that 9 in 10 Virginians support background checks for all gun purchases, GOP legislators have consistently refused to close a yawning loophole in state law that requires no such checks for any firearms purchase from private sellers.

Del. Timothy D. Hugo, a Republican who represents a suburban district straddling Fairfax and Prince William counties, has backed those and other pro-gun positions during his 10 terms in office. He opposed allowing localities to regulate firearms without Richmond’s permission and voted to allow concealed handguns to be carried inside bars and restaurants that sell liquor. As the third-ranking Republican in the House of Delegates, he also helped orchestrate the party’s abrupt shutdown of a special legislative session on gun safety measures last month, called by Gov. Ralph Northam (D) after the Virginia Beach massacre.

Those stances have earned Mr. Hugo an A rating from the National Rifle Association. They’ve also proved awkward for Mr. Hugo, who was reelected in 2017 by just 106 votes out of roughly 30,000 cast. This year, he faces a formidable opponent, Democrat Dan Helmer, a U.S. Military Academy graduate who served in Afghanistan and Iraq.

Faced with the dawning realization that he is radically out of step with his constituents, Mr. Hugo is belatedly making a gesture meant to convey that he is open to sensible gun regulations — his record notwithstanding. Having opposed tough “red flag” bills in the past — measures to keep firearms out of the hands of those who pose a risk to themselves or others — he now sayshe favors one. In fact, the bill, proposed by another suburban Republican battling to keep his seat, mostly tracks existing mental-health laws. It would do little to keep guns from dangerous and violent people who have not been diagnosed as mentally ill.

There are other reasons to oppose Mr. Hugo, who has blocked key measuresto improve transportation and shocked even GOP colleagues by using campaign funds (read: special-interest cash) for snacks, groceries, gas fill-ups and other daily expenses. His extreme record on firearms suggests he has not gotten the message that gun violence is a mortal threat to the public. Perhaps Northern Virginia voters will deliver it.