Ginsburg was asked about her SOTU catnap Thursday at George Washington University, where she and her colleague Justice Antonin Scalia were interviewed by NPR.

"The audience for the most part is awake because they're bobbing up and down all the time. And we sit there, stone faced, the sober judges," Ginsburg said. "But we're not, at least I was not, 100% sober."

She explained that the justices have dinner together before the annual speech, which she said Scalia hadn't attended in several years, and that Justice Anthony Kennedy brought along a bottle of California wine that was just too good to resist.

"I vowed this year — just sparkling water, stay away from the wine — but in the end the dinner was so delicious it needed wine to accompany it."

Ginsburg also blamed wine for her dozing off during Obama's 2013 State of the Union address.