The United States Supreme Court will not hear a challenge to Tennessee's lethal injection method, officially ending a battle over the controversial drugs used to kill death row inmates here.

That decision came days before death row inmate Donnie Edward Johnson, 68, is scheduled to die. Had the high court agreed to hear the case, it might have delayed his execution.

The challenge, brought by Johnson and 22 other death row inmates, argued that the state's three-drug protocol, led by the sedative midazolam, does not keep inmates from feeling excruciating pain as they die. The pain is so severe, they say, that it is unconstitutional.

Tennessee courts rejected the inmates' lethal injection challenge in 2018, saying the inmates had failed to prove another method was available.

The inmates appealed to the nation's high court, saying their efforts were doomed by a Tennessee law shielding details about how the state gets lethal injection drugs.

The inmates argued the law violated their due process and made it impossible for them to meet the requirement to identify other available execution drugs.

The Supreme Court on Monday denied the request to hear the case. But Justice Sonia Sotomayor dissented, saying "the Court again ignores the further injustice of state secrecy laws denying death-row prisoners access to potentially crucial information."

Sotomayor has repeatedly supported arguments from Tennessee inmates, and on Monday she reiterated her belief that it is "perverse" to require inmates to provide an alternative execution method before they can successfully challenge an existing method.

"I continue to believe that the alternative method requirement is fundamentally wrong —and particularly so when compounded by secrecy laws like Tennessee’s," she wrote.

Reach Adam Tamburin at 615-726-5986 and atamburin@tennessean.com. Follow him on Twitter @tamburintweets.