The two major-party candidates for Virginia attorney general, Democrat Mark Herring (left) and Republican Mark Obenshain, participate in a campaign debate hosted by the Loudoun County Chamber of Commerce at the National Conference Center on Oct. 2 in Leesburg. (Jahi Chikwendiu/The Washington Post)

With their candidate for governor down in the polls and their nominee for lieutenant governor widely considered a long shot, Virginia Republicans see Mark D. Obenshain as their best hope for blocking a Democratic sweep of statewide offices.

Obenshain, a state senator from Harrisonburg, is in a tight race for attorney general against state Sen. Mark R. Herring (D-Loudoun). And while his victory is by no means ensured, his chances look better than those of his ticketmates: Attorney General Ken Cuccinelli II, who is running for governor; and E.W. Jackson, a Chesapeake minister running for lieutenant governor.

That view has solidified in recent days, so much so that a national Republican group pumped an astonishing $660,000 into his campaign, according to records released Friday by the nonprofit Virginia Public Access Project.

“He’s clearly running ahead” of other Republicans, said former congressman Thomas M. Davis, who is hosting a fundraiser for Obenshain at his Vienna home Wednesday. “He plays well with others. He’s certainly conservative, but he’s been a unifying force in the party. He’s not been a polarizing figure.”

Republicans have been cheered to see Obenshain attract support from some of the moderate members of the GOP who crossed party lines to endorse Democrat Terry McAuliffe over Cuccinelli. Dwight Schar, part-owner of the Washington Redskins and former national finance chairman of the Republican National Committee, wrote a big check to McAuliffe this year — and another to Obenshain.

Schar serves on the host committee for the fundraiser at Davis’s home. Former Republican senator John W. Warner, who, like Davis, hails from the party’s moderate wing, is scheduled to attend.

Republicans have not given up hope on the rest of their ticket, particularly when it comes to Cuccinelli. All three Republicans can win, some say — particularly if turnout overall is low but Jackson’s tea party fans turn out in droves.

“If the base turns out, and it’s only 30 or 35 percent [overall] turnout, maybe we’re in a squeaker and Ken pulls it off,” one Richmond Republican said on the condition of anonymity to speak candidly.

Another noted that with polls showing Libertarian Robert Sarvis in the low double digits, the numbers could swing big on Election Day if those voters ultimately opt against the third-party candidate.

But everyone seems to feel better about the prospects for Obenshain, who has a family legacy, plenty of campaign cash and a positive message on his side.

Obenshain’s campaign signs bear a slanty, stylized ‘O,’ the same one his father used in the U.S. Senate bid that ended with a plane crash in 1978 (and launched Warner’s Senate career).

In gatherings with Republicans, Obenshain has joked that the “O” reminds some of the Democrat who took Virginia's presidential contest last year. No fan of President Obama or his health-care law, Obenshain tells Republican audiences that it’s time to take back not only our country but our alphabet.

(Obenshain also has a renowned sister, Kate Obenshain, a former chairwoman of the state GOP and occasional contributor on Fox News.)

“Are you ready to stop ­Obamacare in its tracks?” the candidate asked the convention crowd that endorsed him in May. He promises to protect gun rights and to stand up to federal “overreach” — stances with big appeal to the tea party but less to suburban swing voters.

But he has mostly pushed noncontroversial issues: promoting ethics reform and cracking down on sex offenders, human traffickers and abusers of the elderly. His broader message — conveyed in TV ads with his daughter behind the wheel as campaign driver — is upbeat and middle-of-the-road, said Virginia Tech political scientist Craig Leonard Brians.

“That is an incredible ad,” said Brians, referring to a spot with Tucker Obenshain saying her dad encouraged her independence. “This is an empowered girl. She might be 24 or something, but she can speak for the whole family. She doesn’t need a guy to speak for her. And she’s defending her dad.”

Herring’s campaign would agree that the ad is incredible — in the sense that viewers should not believe what they see. They say Obenshain has soft-pedaled his record on abortion and other issues. Herring has tried to highlight Obenshain’s support for ­anti-abortion measures, including sponsorship of a bill, which Obenshain later withdrew, that would have required women to report a miscarriage to police.

Herring is fond of saying that Obenshain votes “like E.W. Jackson talks.”

“My opponent, Sen. Mark Obenshain, would be a continuation of Cuccinelli’s approach,” Herring said in a Richmond Times-Dispatch guest column last week. “He himself has stated that he and Ken Cuccinelli are like ‘two peas in a pod, philosophically’ and that he would ‘take the baton from Ken, build on his work, without missing a step.’ ”

Ben Pershing contributed to this report.