A Supreme Court known for its impatience with death row appeals surprisingly halted two executions this week and is on track to issue four significant rulings on capital punishment by summer.

One Florida case asks the justices to ban the electric chair. Two Virginia cases focus on a federal law aimed at speeding up executions. The fourth case, also from Virginia, asks whether a person can be sentenced to die by a jury admittedly confused about a judge's instructions.

On Tuesday, the court halted an imminent Florida electrocution and agreed to use that death row inmate's case to decide whether death in the electric chair amounts to unconstitutionally cruel and unusual punishment.

On Thursday, an hour before Virginia inmate Michael Wayne Williams was to have died by injection, the justices ordered the execution postponed and said they will fully review his case. At issue is federal court access for state prisoners, which was sharply limited by the 1996 Antiterrorism and Effective Death Penalty Act.

In another Virginia case, Terry Williams is questioning how much discretion Congress wanted federal judges to have in reconsidering state courts' findings, particularly over the adequacy of the legal help a defendant received.

While both Virginia cases are narrowly focused, the court's decision in each could affect hundreds of inmates nationwide.

In the third Virginia case, Lonnie Weeks Jr. says he was condemned after a judge refused to tell jurors they were not required to vote for death just because they had made a certain factual finding. The jury had told the judge it had not fully understood the sentencing instructions.

And the justices could agree as early as Monday to tackle a pair of appeals from Nebraska and Florida that contend that keeping a convicted killer on death row for a long time--decades after his conviction and sentence--amounts to unconstitutional cruel and unusual punishment.

Death row inmates in Arizona and Texas failed to win last-minute Supreme Court help this week. Those two executions raised the year's total to 83, the most since 1954. Nationwide, about 3,600 convicted killers await execution.