Republican presidential candidate Donald Trump talks with attendees at a rally in front of the USS Wisconsin in Norfolk, Va. (Sara D. Davis/Getty Images)

A federal judge on Monday added the Republican Party of Virginia to a lawsuit filed last week by Donald Trump supporters over a loyalty pledge GOP primary voters must sign.

Three African American pastors who support the outspoken presidential candidate sued the state over a requirement that voters must sign a statement affirming that they are Republicans before they can cast a ballot on Super Tuesday, March 1.

The lawsuit names the three members of Virginia’s Board of Elections as defendants because they finalized and will oversee the administration of the pledge at the polls. It reads: “My signature below indicates I am a Republican.”

But M. Hannah Lauck, a judge for the U.S. District Court for the Eastern District of Virginia, added the state Republican Party of Virginia because nothing could be done about the pledge without its participation.

“Factually, both plaintiffs and defendants contend that the language to be used on the ballots arises as a result of the RPV’s involvement,” Lauck wrote in the four-page order.

A hearing on the matter is set for Wednesday in Richmond. The judge will also consider whether the state elections board members should be defendants.

The party’s spokesman, David D’Onofrio, said counsel is reviewing the order and declined to further comment.

For the first time since 2000, the party’s governing board decided in September to impose the pledge. In Virginia, where voters do not register by party, activists have long been divided over the concept.

Supporters say it keeps Democrats and independents from having a say on the Republican nominee; opponents say a state-run primary should be open to all.

Trump catapulted the issue to national significance last month when he tweeted his displeasure with the pledge, which he called a “suicidal mistake.” The pledge could be particularly damaging to Trump, because his un­or­tho­dox candidacy has attracted voters disenchanted with traditional party politics.

In the lawsuit, the pastors — Stephen A. Parson, Bruce L. Waller Sr. and Leon Benjamin — say the pledge will discourage minority voters and those who are poor from casting ballots. They further allege it will create long lines at the polls, imposes “the burden of fear and backlash” and amounts to a literacy test.