Speaker of the North Carolina House of Representatives, Thom Tillis (R-Mecklenburg), addresses attendees March 6 during Wilson County's Republican Convention. (Brad Coville/The Wilson Times via AP)

North Carolina House Speaker Thom Tillis (R) leads a crowded Republican field for the right to face Sen. Kay Hagan (D) in November, according to a new survey conducted for a super PAC backing his campaign.

Tillis scored 27 percent of the vote, compared with 16 percent for physician Greg Brannon and 10 percent for state Baptist Convention President Mark Harris. A handful of other candidates received only single-digit support.

The poll was conducted this week by veteran GOP pollster Jan van Lohuizen, who also conducts surveys for Senate Minority Leader Mitch McConnell. It was commissioned by American Crossroads, the super PAC run by former McConnell chief of staff Steven Law; Crossroads is running $1.1 million in ads backing Tillis in advance of the May 6 primary.

Tillis is the preferred candidate of the National Republican Senatorial Committee, which hopes he can score the 40 percent necessary to win the primary outright and avoid a July 15 runoff. He'll get another boost later this month when the Chamber of Commerce formally endorses his candidacy on April 21, according to two sources with knowledge of the chamber's plans.

A Republican operative privy to the poll results shared the survey with The Washington Post. Crossroads wouldn't comment on the poll, and a chamber spokeswoman wouldn't comment on the race.

Both Harris and Brannon have attacked Tillis in recent weeks as they try to get to his right. But with two candidates vying for the same slice of the electoral pie, most observers think they are just serving to deny each other the oxygen necessary to force Tillis into a runoff.

The Crossroads poll showed a recent civil judgement that found Brannon owes nearly a half-million dollars to two investors in a startup company he ran can be a powerful attack if Brannon's rise begins to challenge Tillis. About four in five voters said the judgement made them less likely to vote for the physician.