Virginia gubernatorial hopefuls Ken Cuccinelli, left, and Terry McAuliffe share a light moment after appearing at a luncheon sponsored by the Virginia Public Access Project on May 30. (Joe Mahoney/The Richmond Times-Dispatch via AP)

In a rare joint appearance by Virginia’s gubernatorial candidates, Attorney General Ken Cuccinelli II and businessman Terry McAuliffe used a Thursday event designed to promote transparency in government to attack each other on the subject.

Cuccinelli (R) and McAuliffe (D) delivered back-to-back speeches at an annual luncheon to benefit the Virginia Public Access Project, a nonpartisan group that publishes campaign finance data and other information about candidates and officials.

Speaking first in the Richmond Marriott Ballroom, Cuccinelli seized on McAuliffe’s alleged disclosure failures, including not releasing his full tax returns.

“So far in the governor’s race,” Cuccinelli said, “I’m the only candidate to be transparent on his tax returns. I’m the only one to be transparent about his own mistakes and to speak clearly — including widely addressing media questions — about substantive policy proposals. And to commit to debates, open debates in all parts of the commonwealth.”

Cuccinelli’s words echoed a series of accusations his camp has repeatedly made against McAuliffe and underscored the intensity of this year’s political contest. The Republican released eight years of tax returns (although reporters were allowed to view them only in his campaign headquarters), while McAuliffe released only summaries of three years’ worth of returns. McAuliffe previously said he would participate in five debates, but Cuccinelli has challenged him to 15 across the state.

“I did it because I believe voters deserve a thorough look at both candidates and the decisions we’ve made in our own lives. . . . It’s not a gimmick, it’s not a trick, it’s important, ” Cuccinelli said.

Speaking to reporters after the luncheon, McAuliffe questioned Cuccinelli’s motives.

“This is another gimmick by Ken Cuccinelli,” the Democrat said, accusing the Republican of using the tax and debate issues to distract from his transparency problems.

Those include Cuccinelli’s initial failure to disclose his stock ownership in Star Scientific, a dietary supplement firm at the center of multiple investigations, and his incomplete disclosure of gifts from Jonnie R. Williams Sr., the company’s chief executive.

“Before you come back and ask me, he has not done what he was required to do by law and disclose the gifts he received [from] Star Scientific,” McAuliffe said. “That’s the issue.”

Cuccinelli noted that he eventually fixed both disclosure errors.

“I put those out on my own volition,” Cuccinelli said. “Nobody found those. I found those, and I went back and made my mistakes and put them out there. . . . I actually think that’s an exercise in transparency. You think I enjoyed that? I didn’t, but you’ve got to own up to those mistakes when you make ’em.”

In his luncheon address, McAuliffe made only passing reference to the subject Cuccinelli had emphasized.

“Transparency is important, and, as you know, I’ve also called for an ethics commission when I am elected governor to make sure that we’re taking these thorny issues outside the state government,” McAuliffe said.

He then gave a version of his standard stump speech, emphasizing the need to improve Virginia’s economy by bolstering education and workforce training. He praised the bipartisan transportation bill advanced by Gov. Robert F. McDonnell (R) and criticized by Cuccinelli because it raises taxes.

The Democrat also said he would accept federal money to expand Medicaid coverage, calling it the right thing to do “morally and socially” and a potential boon to the state economy.

McAuliffe took a swipe at the broader Republican message, which has been affected by the nomination of E.W. Jackson for lieutenant governor. The 61-year-old Chesapeake minister has made controversial statements on race, abortion and homosexuality.

“We cannot grow our economy with a social, ideological agenda,” McAuliffe said. “We cannot have this divisive rhetoric that had come out of the General Assembly last year and this year. We cannot be attacking women. We cannot be putting walls up around Virginia. We cannot be attacking members of the LGBT community.”

Speaking afterward, Cuccinelli denied that the Jackson nomination has had an impact on his campaign.

“It doesn’t change our message a lick,” Cuccinelli said. “He’s got to defend all his own statements, and he’s going to go about doing that, but we run our own race.”