The Senate Republicans' campaign arm is threatening GOP consulting firms not to work against Sen. Luther Strange in the upcoming primary election.

The National Republican Senatorial Committee, which recruits and defends Republican candidates, could not immediately be reached for comment. Politico first reported on the NRSC's stance.

"We have made it very clear from the beginning that Sen. Luther Strange would be treated as an incumbent," NRSC spokeswoman Katie Martin told Politico, according to remarks posted by the Andalusia Star. "It has also been a clear policy that we will not use vendors who work against our incumbents."

Rep. Ed Henry, R-Hartselle, who is among three challengers to Strange so far, confirmed the facts of the report to AL.com.

"I've run across a few [consultants] that do work for [the NRSC] and they're not willing to take on anybody that would get them in trouble with [the NRSC]," Henry said. The state lawmaker said he was rebuffed by D.C. consultants and will pick from two Alabama-based consultants to assist his campaign.

The NRSC's push to make it more difficult for Strange's opponents to hire political consultants gives the senator a larger advantage in holding on to his seat as the summer's special election looms.

"If [Strange is] going to have $10 million worth of TV ads bombarding the state of Alabama, and no one in the state of Alabama has the ability to compete with that type of media presence, [then] Washington, D.C., through Luther Strange, will be dictating what the message is, and it's just another example of how far our country has fallen," Henry said.

Strange has been a senator for nearly four months after he was appointed by then-Gov. Robert Bentley to fill the seat left vacant by Jeff Sessions, who left the Senate to be President Donald Trump's attorney general.

Aside from Henry, Christian Coalition of Alabama president Dr. Randy Brinson, and former Alabama Chief Justice Roy Moore have announced they are running for the Senate seat.

Strange will be well-funded for the special election; he has more than $763,000 cash in hand in his campaign account.

"Anyone who runs against Luther is going to have every oppo shop in DC and elsewhere digging up their past and airing their dirty laundry," said West Honeycutt, a D.C. political consultant and Alabama native.