Ken Cuccinelli, Virginia attorney general and GOP candidate for governor, speaks April 17 at the Wakefield Sportsmen's Club in Wakefield, Va. (Patrick Kane/AP)

In a state where party registration doesn’t exist, the idea that Virginians should have to pick a side has an important champion — the potential next governor.

Attorney General Ken Cuccinelli II, the GOP nominee for the commonwealth’s top job, reiterated Tuesday that he thinks that Virginia should change its system to make voters officially choose a party or declare themselves independent, so that parties could ensure that only their own members vote in their primaries.

Cuccinelli backed the idea when he was in the Senate, too, but come January he could be in a more important position if he defeats Democratic nominee Terry McAuliffe.

“I’ve encouraged that in the past and I’ll encourage it in the future,” Cuccinelli said after speaking at the Greenspring retirement community in Springfield.

While Cuccinelli said he couldn’t guarantee a change in state law, as governor, “If nothing else, you’re the final gatekeeper.”

The subject arose after a resident at Greenspring — which boasts its own election precinct and historically high turnout — asked Cuccinelli why Virginia Republicans did not have a primary this year to pick statewide nominees. While Cuccinelli was unopposed, the GOP picks for attorney general and lieutenant governor were made at a May convention in Richmond.

Republicans had originally planned to hold a primary, but Cuccinelli allies on the state GOP central committee last year successfully pushed to hold a convention instead, which tends to favor more conservative candidates. Cuccinelli’s rival for the gubernatorial nomination, Lt. Gov. Bill Bolling, dropped out of the contest in part because of that change.

Cuccinelli didn’t quite say Tuesday whether he had endorsed that decision, though he noted that he had a wide polling lead over Bolling and predicted that there “probably wouldn’t have been a different outcome” if there had been a primary. He also noted, as convention defenders often do, that the costs of primaries are borne by taxpayers and that primary campaigns are much more expensive for the candidates than convention campaigns are.

“I think you’d probably see more commitment to primaries by the Republican Party versus conventions … if we had party registration,” Cuccinelli said. “Incumbents in Richmond have blocked party registration because incumbents tend to want anybody to be able to show up, because they want to have protection from their party regulars. And they get that from people who aren’t members of their party.”

Legislation to change the current system has surfaced repeatedly in the General Assembly but has never made it very far. A 2012 bill requiring voters to register by party or declare themselves independents was defeated in the Senate and never came to a vote in the House.

Asked for McAuliffe’s position on the subject, McAuliffe spokesman Josh Schwerin said: “Terry is focused on how we grow and diversify the economy, not on changing party registration regulations.”