WASHINGTON -LRB- CNN -RRB- -- Sen. Larry Craig filed an appeal Monday in his continued legal fight stemming from a bathroom sex sting this summer . Sen. Larry Craig , R-Idaho , initially said he would resign at the end of September but then changed his mind . The Idaho Republican wants the Minnesota Court of Appeals to overturn a judge 's decision refusing to let him withdraw a guilty plea to misdemeanor charges stemming from his arrest in June . `` From the outset Senator Craig has maintained that he is innocent of any illegal conduct at the Minneapolis airport , '' Craig 's lawyer , Billy Martin , said in a written statement . `` Like every other citizen , Senator Craig has the constitutional right to make every effort to clear his name . '' Martin called the judge 's decision `` a manifest injustice . '' In an interview Sunday with Boise , Idaho , TV station KTVB , Craig said `` we do n't know what the appellate court will say to me , '' according to the station 's Web site . Watch Craig discuss his chances on the appeal '' `` Honestly , the appeals courts tend to defend the courts below them . It is my right to do what I 'm doing . I 've already provided for Idaho -LSB- the -RSB- certainty that Idaho needed , I 'm not running for re-election . I 'm no longer in the way . I am pursuing my constitutional rights . '' The appeals process could take months to complete , court spokesman Kyle Christopherson said . Craig entered a guilty plea after his arrest in a men 's room at the Minneapolis-St . Paul International Airport for allegedly propositioning a plainclothes police officer for sex . Craig originally said he would resign from the Senate on September 30 if he could not get the guilty plea withdrawn . He later postponed his decision until the judge ruled . After an October 4 ruling against him , Craig changed course , saying he would not resign and would continue to pursue his legal options . `` I am innocent of the charges against me , '' he said at the time . The Idaho lawmaker 's decision not to resign has created a political headache for the Senate 's Republican leadership . When news of the arrest first surfaced , GOP leaders called for an investigation by the Senate Ethics Committee . They later applauded Craig 's decision to resign . And when Craig announced that he would continue to serve in the Senate , GOP leaders did not appear pleased . `` It 's embarrassing for the Senate . It 's embarrassing for our party , '' said Sen. John Ensign of Nevada , who leads the GOP 's Senate campaign committee , on the day of the judge 's decision . `` I think it 's best for the U.S. Senate , it 's best for certainly his party , that he just keeps his word . '' Romney accused In an interview taped Sunday with NBC 's Matt Lauer , Craig complained that GOP presidential candidate Mitt Romney `` threw me under the campaign bus '' when news of his arrest came out . `` He not only threw me under his campaign bus , he backed up and ran over me again , '' Craig told Lauer in the interview set to run Tuesday night , according to MSNBC.com . Romney , former governor of Massachusetts , called Craig 's behavior `` disgraceful '' and urged the senator to resign when news of the arrest broke in August . Craig was Romney 's Senate liaison before resigning from the campaign . Romney spokesman Kevin Madden defended the presidential candidate 's response . `` Gov. Romney simply believes that a public office is a public trust , '' Madden said . `` He believes when a public official enters a guilty plea , they have broken that public trust and should step aside for the sake of their constituents . '' Also in the Lauer interview , Craig and his wife , Suzanne , denied that their marriage is a cover for his homosexuality , according to MSNBC.com . `` People know me and know that I would never do that , '' said Suzanne Craig , MSNBC.com reported . `` That 's almost like selling your soul for something . '' The senator has denied he is gay . `` I love this woman very , very much , '' Larry Craig said , according to MSNBC.com . `` The day I found her , I fell deeply in love . And we 're heading toward our 25th anniversary . '' When she learned the story was going to break , Suzanne Craig said , `` I felt like the floor was falling out from under me . ... And I felt like almost like I was going down a drain for a few moments , '' according to MSNBC.com . E-mail to a friend CNN 's Scott Anderson and Alexander Romney contributed to this report .