The 57-year-old man was convicted in 2010 of first-degree sexual assault against his niece when she was 5 or 6 years old.
A state appeals court ruled in 2012 that the man deserves a new trial because the judge mistakenly instructed jurors they didn't have to agree on where the assault happened. The appeals court said the jury had to unanimously agree the assault took place in the laundry room.
But a unanimous Supreme Court on Wednesday disagreed, saying the jury did not have to agree on the location of the assault.
The Associated Press isn't naming the man to avoid identifying the girl.