Adam Savader of Great Neck, N.Y., was accused of threatening to release nude photos of young women unless they sent some to him. Many were college students in Michigan and elsewhere who knew him from various schools.
Savader last week pleaded guilty in Detroit federal court. Guidelines call for at least two years in prison when he returns March 13, although the judge has discretion.
Savader admits using an alias while sending text messages over a Google phone service. He got access to nude photos through hacked accounts that belonged to the women.
The 21-year-old was a Republican activist who worked for 2012 presidential candidates.