Like you, I oppose these provisions.  Section 1031 is problematic because it authorizes the indefinite detention of American citizens without due process.  In this democracy, due process is a fundamental right, and it protects us from being locked up by the government without charge.
For this reason, I offered an amendment to prohibit the indefinite detention of U.S. citizens without trial or charge.  Unfortunately, on December 1, 2011, this amendment failed by a vote of 45-55.
I was, however, able to reach a compromise with the authors of the defense bill to state that no existing law or authorities to detain suspected terrorists are changed by this section of the bill.  While I would have preferred to have restricted the government’s ability to detain U.S. citizens without charge,this compromise at least ensures that the bill does not expand the government’s authority in this area.