A judge has put a temporary stop to South Dakota's new riot booster law aimed at Keystone XL pipeline protesters.

U.S. District Judge Lawrence Piersol granted a preliminary injunction on Wednesday in a lawsuit against Gov. Kristi Noem and Attorney General Jason Ravnsborg alleging the state's riot laws, which allow the state to sue "riot boosters" including on behalf of a third party, were unconstitutional. Piersol also denied the state's request to certify the question to the South Dakota Supreme Court and he granted Pennington County Sheriff Kevin Thom's motion to dismiss the case against him, leaving Noem and Ravnsborg as the sole defendants.

The state has an interest in criminalizing participation in a riot, but the state's laws defining a riot "go far beyond that appropriate interest and ... do impinge upon protected speech and other expressive activity as well as the right of association," Piersol wrote in his order.

The American Civil Liberties Union of South Dakota filed the lawsuit on behalf of four groups and two individuals. ACLU attorney Stephen Pevar said they're "thrilled" by Piersol's injunction.

"What it means for everybody is that they can speak their minds about the pipeline without fear of going to prison," Pevar said. "This has never been about breaking the law. Our clients simply want to engage in peaceful protest, but under these statutes, they can't do that without fear of punishment. The statutes just go too far."

Noem and her team are reviewing Piersol's ruling and because the issue remains in litigation, Noem isn't commenting on the matter at this time, according to Noem's spokeswoman Kristin Wileman.

More:ACLU, South Dakota head to court over Keystone XL pipeline protest law

The ACLU is asserting in the lawsuit that the state's three protest laws violate the First and 14th Amendments of the U.S. Constitution by chilling protected speech and failing to describe the speech and conduct that would subject protesters to criminal and civil penalties.

The injunction only prevents the state from enforcing parts of the laws Piersol found to be unconstitutional while the lawsuit moves forward through the legal process. Piersol wrote in his order that the state can hold someone liable for "directing" a riot, but not for encouraging, advising or soliciting people to riot.

State's motives and language

Piersol questioned who benefits from the state's riot boosting laws and whether the goal is keep "outsiders" out of South Dakota, which he says isn't "a laudable goal" considering citizens in all 50 states have the same right of free speech and assembly. Concerns are valid about potential costs incurred by the counties if there are protests, but those concerns are speculative at this point, he wrote. He also pointed out that Keystone XL personnel could financially benefit if the state sues riot boosters and that doesn't meet public policy concerns applicable to taxpayers.

"By comparison, the freedom of speech and association are constitutional rights that are central to all citizens of our country. Those rights will be thwarted if the unconstitutional portions of the riot boosting legislation remain in effect," Piersol wrote.

In granting the injunction, Piersol considered that planning and seeking support for Keystone XL protests would need to take place now, ahead of the next construction season, and those who favor the pipeline should have an opportunity to respond — instead of all of the confrontations taking place during the pipeline's construction.

More:Judge hears case challenging South Dakota's protest laws

At issue in the lawsuit are the state's new "riot boosters" laws, introduced and passed in a 72-hour period in the final full week of this year's legislative session, and the state's two existing riot law on which the new riot booster law is based. Noem proposed the riot boosting legislation during the session, saying that its purpose is to ensure that the Keystone XL pipeline is built through South Dakota in a safe manner while the state, counties, water, environment and people are protected during the construction.

In March, lawmakers urged the quick passage of the new riot booster law before the legislative session's end because construction could begin before the 2020 session began, although the Keystone XL's construction was tied up in court at the time. Piersol pointed out in his order on Wednesday that the Legislature has time to pass a riot law during the 2020 session that meets constitutional requirements before the pipeline's construction begins.

Piersol narrowed in on the law's definition of riot booster as someone who advises, encourages or solicits people. He wrote that those actions are protected by the First Amendment and can't be subject to felony prosecution because they're too broad.

"Sending a supporting email or a letter to the editor in support of a protest is encouraging. Giving a cup of coffee or a thumbs up or $10 to protesters is encouraging the protesters. Holding up a sign in protest on a street corner is encouraging. Asking someone to protest is soliciting," Piersol wrote, pointed out that Martin Luther King Jr. would have been liable for "riot boosting" under South Dakota's law for writing his "Letter from Birmingham Jail."

If the state had only included the word "direct," instead of also including encouraging, advising or soliciting people to riot, it would have been a different story legally and the Legislature would have still passed the bill if a riot booster was defined as only directing a person to riot, according to Piersol.

"The Legislature was strongly motivated to pass the riot boosting legislation. The bill was introduced in the last week of the session, long after the deadline for introducing legislation. The bill advanced to votes with only one hearing and the bill contained an emergency clause to make it immediately effective," he wrote.