Attorney General Jay Nixon said this means lethal injections should be carried out in Missouri again. 

Rita Linhardt, a representative of the Missouri Catholic Conference said the court's ruling does not address whether or not lethal injection should be used at all. She also said the ruling does not look at innocent people on death row, or racial bias in the judicial system. 

Greg Mermelsten, from the State Public Defenders Office, said he thinks the fight against legal injections will continue. 

"A lot of the challenges we've seen here in Missouri have been in federal court, challenging lethal injection," said Mermelsten. "And I suspect those challenges are going to continue, but they're gonna continue in a different fashion because attorneys are going to need to now adjust their legal strategy based on what the Supreme Court has said."

Michael Taylor could be Missouri's most well-known death row inmate. That is because he and his lawyers have used the same lethal injection argument to try to get him off of death row. The argument is that the lethal injection drugs can cause excruciating pain.

Wednesday's U.S. Supreme Court ruling will not affect Taylor's case. The High Court will review that case later this year.