Questions and concerns continue to be raised about the system of capital punishment in the United States.

The latest major challenge to the way the death penalty is carried out in most states is now before the U.S. Supreme Court. The court last week agreed to review a case from Kentucky in which two death-row inmates claim that execution by lethal injection is contrary to the Eighth Amendment prohibition against cruel and unusual punishment.

At issue is the three-drug cocktail used for lethal injection in Kentucky and many other states. The three drugs are an anesthetic to make the inmate unconscious, a second that is a paralyzing agent and a third that stops the heart and causes death.

The complaint filed by Kentucky death-row inmates Ralph Baze and Thomas C. Bowling contends the chemicals and procedures used create “an unnecessary risk of pain and suffering” in violation of the Eighth Amendment.

The Kentucky Supreme Court upheld the method of lethal injection last year in a 7-0 decision. This opinion said the constitutional prohibition against cruel and unusual punishment “does not require a complete absence of pain.”

The U.S. Supreme Court is expected to hear oral arguments in the Kentucky case early next year with a decision later in 2008. The case is significant because the only time the high court has ruled directly on a method of execution was in 1878, when it upheld the use of the firing squad.

The case filed by Baze and Bowling also is important because it comes at a time when there are challenges to lethal injection in many other states, and some court rulings have put a hold on state executions.

For example, a week before the Supreme Court agreed to review the Kentucky case, U.S. District Judge Aleta Trauger ruled unconstitutional Tennessee’s method of execution by lethal injection, saying it “presents a substantial risk of unnecessary pain.” Trauger said the new protocol adopted in Tennessee does not ensure that inmates are properly anesthetized before the lethal injection is administered, and this could “result in a terrifying, excruciating death.”

And last week, Alabama Gov. Bob Riley ordered the stay of an execution of an inmate while the state comes up with a new formula for lethal injection to make sure prisoners are completely unconscious before they are killed. A spokesman for the governor said Alabama’s method of execution was similar to the one in Tennessee that was ruled unconstitutional.

Also last week, the U.S. Supreme Court halted an execution in Texas while it reviews the lethal injection procedures in the case from Kentucky. Texas leads the nation in the number of executions.

It’s somewhat ironic that lethal injection has in recent years become execution method of choice in this country because it was considered to be “more humane” than other methods, such as electrocution or the gas chamber. As it was argued in the Kentucky General Assembly about a decade ago, when lethal injection was adopted as the preferred method of execution, if we are going to have the death penalty we should make it as “humane” as possible.

Now, questions and concerns are being raised across the country about whether this “humane” method of killing is as “humane” as it’s advertised. Is one method of lethal injection “more humane” than another so that it’s not cruel and unusual punishment? If so, what is this “magic” solution?

It remains to be seen what direction the Supreme Court takes in deciding the case from Kentucky. In the meantime, this growing quagmire over the “most humane” and “most constitutional” way to execute someone by lethal injection could be resolved by tossing out the death penalty completely and replacing it with life in prison without parole.

After all, the real issue here is — or should be — the act of state-sanctioned killing itself. This is what Kentucky and the other states that have capital punishment should consider.

As former Kentucky legislator Bob Heleringer said during the legislative debate on lethal injection some years ago, “There’s nothing better or more humane about killing; that’s what we are talking about.”