San Jose, Calif. ? With execution chambers from California to Florida idled, the U.S. Supreme Court on Monday will offer an unprecedented glimpse into how the justices assess the swirling legal conflict over the grim business of administering a fatal dose of drugs to death row inmates.

The Supreme Court, faced with mounting legal chaos across the country over lethal injection, will hear arguments in a challenge to Kentucky’s execution method – the same procedure favored in virtually every state that has a death penalty. The justices will directly confront the constitutionality of an execution method for the first time since the 1870s, when they upheld Utah’s firing squads.

The court is expected to rule by the end of its term in June, at the very least devising a road map for what states must do to ensure the executions they carry out are as humane as possible.

On one side, lawyers for death row inmates argue that states have grown so sloppy in executions that they should not resume unless the Supreme Court establishes strict standards. On the other side, dozens of states, the Bush administration and victims’ rights groups insist that Kentucky and other states already do it right.

For legal experts, the tea leaves have never been harder to read. There is only one consensus: The conservative Supreme Court will not abolish the death penalty or outlaw lethal injection.

The question is how far it will go in forcing states to fix perceived problems and whether the justices will specify what states must do to tinker with the drugs, training and medical safeguards such as monitoring inmates during executions. There is agreement that the Supreme Court must clear up a legal mess that has effectively created the first nationwide moratorium on executions since the early 1970s.

“It’s very difficult to know whether this court is going to limit itself,” said Elisabeth Semel, head of Boalt Hall School of Law’s Death Penalty Clinic. As for her prediction, Semel admits: “It depends on which day of the week it is or which brief I’ve just read.”

The Supreme Court stepped into the issue last fall after several years of proliferating legal challenges to lethal injection, all centered on whether the three-drug combination used in most executions exposes inmates to the risk of cruel and unusual punishment. Critics argue that the combination of drugs can mask an inmate’s suffering.

Courts throughout the country have issued conflicting rulings, with some states putting executions on hold. The Kentucky case reached the high court after that state’s Supreme Court upheld Kentucky’s lethal injection procedures, opening the door for the justices to tackle the issue.

Twenty states and the federal government, which also uses lethal injection, urged the justices to simply find that Kentucky’s method passes legal muster, and not micromanage the states.