"It helps him connect with a constituency that might regard him skeptically," Cross said.

Among the conservatives who stand behind Craig is Ellen R. Sauerbrey, the two-time Republican nominee for governor and favorite of the party's right wing.

"If people think David is a RINO, I think they're very wrong," said Sauerbrey, who served with Craig in the House of Delegates in the early 1990s when she was minority leader.

Craig has been beefing up his conservative credentials as he has waded deeper into the statewide political scene. When the General Assembly passed a law in 2012 requiring some counties to impose fees to finance projects that would reduce runoff into the Chesapeake Bay, Craig's first reaction was to reluctantly comply. Recently, however, he urged the County Council to repeal the fee that conservatives have derided as a "rain tax." He is making repeal of the fee a central issue of his campaign.

That stance is part of his broader view that Maryland should back off from some of its more aggressive anti-pollution efforts. Craig has challenged Maryland's traditional role of leadership among the states in the bay watershed, questioning whether it should get out ahead of Pennsylvania and New York, which contribute to the bay's pollution but have less stake in its condition.

Craig said the U.S. Environmental Protection Agency should take the lead — but only after the federal government has fixed its own pollution problems and the agency has proved that its rules will be effective. If that means a delay in cleaning up the bay, he said, he sees no urgency.

"Some people would say it's been dirty since the 1830s," he said. "Some people say it's going to be dirty forever."

In a previous interview, Craig had suggested repeal of the 1984 Critical Areas Act, a landmark law limiting development on the land closest to the bay and its tributaries. Last week, he backed off that stance, saying the legislation should be re-examined, not eliminated.

Likewise, Craig dialed back a recent suggestion by an aide that he would give the Department of Business and Economic Development veto authority over regulations proposed by other departments — such as environment, health and labor — if the rules could cost Maryland jobs. Last week, Craig said the business agency would review such rules but would not have a veto.

As Craig has modified stances on a few issues, he's taken a hard-right position on others.

On transportation, he would reserve three of the largest sources of revenue — the gas tax, vehicle registration fees and titling taxes — for spending on roads and bridges, not mass transit. To fund Baltimore-area bus and rail lines, he would require riders to pay 50 percent of the cost of running the system — a proposal that would raise the current base fare of $1.60 to $2.90, according to legislative analysts.

Craig said he would like to see limits on food stamps and other welfare benefits, even when the federal government provides many of the resources.

Todd Eberly, a professor of political science at St. Mary's College in Southern Maryland, has called Craig a strong Republican candidate. But the rightward turn has made Eberly more skeptical about Craig's chances in a general election.

"I still view him as the strongest statewide candidate for the Republicans, but if he's not careful he will completely undo that advantage," Eberly said.

Sauerbrey, who narrowly lost the gubernatorial election to Democrat Parris N. Glendening in 1994, thinks Craig is positioned right where he needs to be to win in November 2014.

"I think he's offering solutions that the state badly needs," she said, "and the majority of people in this state feel sick and tired of being overtaxed and over-regulated."

Baltimore Sun reporter Erin Cox contributed to this article.