CONCORD, N.H. – New Hampshire’s only death-row inmate will have his day in court — all day — when the state Supreme Court hears arguments pertaining to his sentence.

Michael Addison was sentenced to death for gunning down 35-year-old Manchester Police Officer Michael Briggs in 2006, when Briggs tried to arrest him on robbery charges.

The justices in Addison’s case will deliberate the death penalty for the first time in more than 50 years — deciding, among other things, whether Addison’s sentence is just or was a product of passion or prejudice. Addison’s attorneys want the court to vacate his death sentence and order a new sentencing hearing.

The justices will hear arguments in the case beginning Wednesday morning, holding four blocks of hearings, scheduled to end at 3 p.m.

Court observers say the daylong hearing on Addison’s conviction is unprecedented. A typical hearing before the justices lasts half an hour.

If his sentence is upheld and carried out, Addison would be the first convict executed in New Hampshire since 1939.

Former Chief Justice John Broderick, now dean of the University of New Hampshire School of Law, said the court, on occasion, has granted more time for arguments, citing the Claremont school funding cases as examples.

“But an entire day? I don’t know of another case where that’s happened,” he said.