ST. PAUL — A Republican state senator faced with more than $900,000 in debt has filed for bankruptcy.

Sen. Sean Nienow, of Cambridge, and his wife, Cynthia, filed for Chapter 7 bankruptcy last month, according to court records. The Nienows must sell nonessential assets to put the money toward about $931,000 in debt. The filing listed total assets of almost $122,000.

The U.S. Small Business Administration sued the Nienows in January, seeking nearly $750,000 from a loan to the couple’s failed business, the National Camp Association Inc.

Nienow did not return calls to his cell or home phones.

After first winning his seat in 2002, Nienow lost re-election in 2006 but won again in 2010.