The U.S. Supreme Court has been busy this month tinkering with the criminal justice system. The Court rendered three decisions in five days that have implications for the Fourth, Fifth, Sixth and Eighth Amendments.

Initially, the Court, in a 5-4 ruling, rejected the government's limitations on the number of times federal inmates can challenge the legality of their sentence.

Federal habeas corpus law allows inmates to challenge, in federal court, the grounds for their detention. The Antiterrorism and Effective Death Penalty Act (AEDPA) created separate procedures for state inmates seeking relief from their state convictions in federal court and for federal inmates challenging their federal convictions.

Enacted after the Oklahoma City bombing, AEDPA created strict deadlines and deference to state courts in federal reviews, making it harder for inmates to overturn convictions while empowering federal efforts against terrorism. The AEDPA implicates the Fifth Amendment — due process for federal habeas corpus limitations; and the Sixth Amendment — fair trial rights, especially regarding counsel and evidence; and the Eighth Amendment — cruel and unusual punishment.

An unlikely majority of Justices Elena Kagan, Ketanji Brown Jackson, Sonia Sotomayor, joined Chief Justice John Roberts and Justice Brett Kavanaugh found that the AEDPA could limit opportunities for state inmates to challenge their convictions, but could not limit federal inmates from having their convictions reviewed by the court.

Five days later, the Supreme Court entertained a double jeopardy question.

The Fifth Amendment's Double Jeopardy Clause provides that no person shall "be subject for the same offense to be twice put in jeopardy of life or limb." The Double Jeopardy Clause can be invoked to prevent a person from being tried twice for the same offense or, as in the case before the Supreme Court, being punished more than once for the same crime.

A New York man was charged in federal court with using a firearm during a robbery, a crime of violence, and causing death.

All the justices were satisfied that a century-old decision determined that the two charges counted as the same offense. The longtime test for double jeopardy was clear: "whether each provision requires proof of an additional fact which the other does not."

The unanimous decision, written by Justice Ketanji Brown Jackson, found that because using a firearm during a crime of violence does not have any elements not shared by causing death, the double jeopardy clause applies and the defendant cannot be punished for both offenses.

Finally, on the same day, the Supreme Court upheld the conviction of a Montana man who was convicted of assaulting a police officer. In another unanimous decision written this time by Justice Elena Kagan, the court ruled that police officers did not violate the Fourth Amendment when they entered the home of a man without a warrant due to an emergency in the home.

The Court rejected the man's contention that the police officers needed "probable cause" to go into his house. The Fourth Amendment to the Constitution prohibits unreasonable searches and protects a person's home by generally prohibiting law enforcement from entering without a warrant.

Under the Supreme Court's earlier cases, it was enough that the police officers reasonably believed that someone inside a home needed emergency assistance. The court rejected the need for probable cause to enter a home without a warrant and sustained an "objectively reasonable" standard.

Justice Elena Kagan wrote that the police in Montana had acted appropriately when they entered a home without a warrant because they had an "objectively reasonable basis for believing that a homeowner intended to take his own life and, indeed, may already have shot himself."

Matthew T. Mangino is of counsel with Luxenberg, Garbett, Kelly & George P.C. His book The Executioner's Toll, 2010, was released by McFarland Publishing. You can reach him at www.mattmangino.com and follow him on Twitter @MatthewTMangino

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