Virginia Republican gubernatorial candidate Ken Cuccinelli opened CPAC with a call for conservatives to preserve American history and celebrate American exceptionalism. (The Washington Post)

Attorney General Ken Cuccinelli II delivered a populist message to a conservative audience Thursday, as Virginia’s gubernatorial race enters a crucial phase when moderate voters are up for grabs.

Cuccinelli (R) was the first speaker to address the 40th annual Conservative Political Action Conference on Thursday at the Gaylord National Resort at National Harbor, using the national platform to promise that he would “defend our most sacred principles” in his campaign against businessman Terry McAuliffe (D) for Virginia’s top job.

The remarks — part red meat for the base, part stump speech for a broader audience — came two days after Lt. Gov. Bill Bolling (R) announced that he would not make an independent bid for governor, leaving what is essentially a two-man contest between Cuccinelli and McAuliffe. (White House gate-crasher Tareq Salahi says he is running as an independent but neither party is paying much attention.)

Bolling’s potential candidacy was predicated on the idea that he might pull moderates and independents away from Cuccinelli and McAuliffe. His absence leaves a void in the middle, and it’s not clear which candidate will best fill it.

On Thursday, Cuccinelli primarily stuck to his conservative guns at CPAC, even if at times he hit a more populist note.

“Democrats and their liberal allies labeled me someone who must be defeated at all costs,” Cuccinelli said. “One thing that even my staunchest opponents will concede is that I am a straight shooter, and I am a man of my word. And when this race is over, I will still be able to say that.”

As governor, Cuccinelli said, he would cut government regulations, safeguard property rights, expand school choice and “continue efforts to protect our most vulnerable citizens . . . at every stage of life.”

But he also said he would close tax loopholes “for the well-connected.” He said he would crack down on online predators and human trafficking, and he did take his party to task on one front. As a past advocate in Virginia for giving potentially innocent prisoners the chance to clear their names, he criticized fellow “tough-on-crime conservatives” who are “excited to lock people up and throw away the key.”

“Conservatives should lead the campaign to changing the culture of corrections in America,” he said.

Cuccinelli has made a few overtures toward the center. He said on Wednesday that he would not sign the anti-tax pledge promoted by Grover Norquist’s Americans for Tax Reform; his campaign said he opposes higher taxes but would not sign pledges of any sort. And he recently sought to assemble a bipartisan coalition in Richmond to make it easier to get on the Virginia ballot.

Quentin Kidd, a political science professor at Christopher Newport University in Newport News, called Cuccinelli’s address “a reset speech” in which he sought to put his record in a broader context.

“He made this argument about how a principled conservative could appeal to the very electorate that was sort of hanging on the possibility of Bolling running,” Kidd said.

Democrats have sought to peg Cuccinelli as too pugnacious and too conservative for an increasingly purple commonwealth that has frequently supported consensus-building moderates in recent years.

Mark R. Warner (D) and Timothy M. Kaine (D) both won gubernatorial and Senate races following that model. And although Gov. Robert F. McDonnell (R) — who was notably not invited to address CPAC this year — has a largely conservative record, he ran in 2009 with a clear focus on economic policy rather than potentially divisive social issues.

Cuccinelli, by contrast, has drawn conservative grass-roots support and national media attention for wading into a host of thorny debates. He was an early and vocal critic of President Obama’s health-care plan, filing his own unsuccessful lawsuit to challenge its constitutionality. He advised Virginia’s Board of Health to impose strict new building standards on abortion clinics, and he told Virginia colleges that they could not ban discrimination against gays.

More recently, he has criticized a landmark Virginia transportation plan, backed by McDonnell and passed by a bipartisan coalition in the General Assembly, because it raises taxes to pay for roads. The plan was supported by McAuliffe, who seized on the moment to make the case that he is more willing than Cuccinelli is to reach a compromise across the aisle.

Despite prodding from Democrats, Cuccinelli has not taken a final position on the transportation deal and has not said whether he would seek to undo it if elected governor. His campaign notes that the plan could still be amended.

Cuccinelli made no mention of transportation at CPAC, where he described McAuliffe as an “unabashed liberal” who does the bidding of labor unions and views “power as being more important than principle.”

McAuliffe spokesman Josh Schwerin said Cuccinelli’s comments were evidence that he was catering to the fringes of his party.

“Ken Cuccinelli has focused his career on an extreme and divisive ideological agenda, so it shouldn’t come as a surprise that after trying to torpedo Governor McDonnell’s bipartisan transportation compromise he would continue to feel most comfortable surrounded by national tea party activists, not mainstream Virginians,” Schwerin said.