<PAGE>
                                                                 EXHIBIT (31)(a)


                        CERTIFICATION OF KENNETH WHIPPLE


I, Kenneth Whipple, certify that:

     1.   I have reviewed this annual report on Form 10-K/A-1 of CMS Energy
          Corporation;

     2.   Based on my knowledge, this report does not contain any untrue
          statement of a material fact or omit to state a material fact
          necessary to make the statements made, in light of the circumstances
          under which such statements were made, not misleading with respect to
          the period covered by this report;

     3.   Based on my knowledge, the financial statements, and other financial
          information included in this report, fairly present in all material
          respects the financial condition, results of operations and cash flows
          of the registrant as of, and for, the periods presented in this
          report;

     4.   The registrant's other certifying officer(s) and I are responsible for
          establishing and maintaining disclosure controls and procedures (as
          defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the
          registrant and have:

               a) Designed such disclosure controls and procedures, or caused
          such disclosure controls and procedures to be designed under our
          supervision, to ensure that material information relating to the
          registrant, including its consolidated subsidiaries, is made known to
          us by others within those entities, particularly during the period in
          which this report is being prepared;

               b) Evaluated the effectiveness of the registrant's disclosure
          controls and procedures and presented in this report our conclusions
          about the effectiveness of the disclosure controls and procedures, as
          of the end of the period covered by this report based on such
          evaluation; and

               c) Disclosed in this report any change in the registrant's
          internal control over financial reporting that occurred during the
          registrant's most recent fiscal quarter (the registrant's fourth
          fiscal quarter in the case of an annual report) that has materially
          affected, or is reasonably likely to materially affect, the
          registrant's internal control over financial reporting; and

     5.   The registrant's other certifying officer(s) and I have disclosed,
          based on our most recent evaluation of internal control over financial
          reporting, to the registrant's auditors and the audit committee of
          registrant's board of directors (or persons performing the equivalent
          functions):

               a) All significant deficiencies and material weaknesses in the
          design or operation of internal control over financial reporting which
          are reasonably likely to adversely affect the registrant's ability to
          record, process, summarize and report financial information; and

               b) Any fraud, whether or not material, that involves management
          or other employees who have a significant role in the registrant's
          internal control over financial reporting.





Dated:  July 21, 2004                           By:     /s/ Kenneth Whipple
                                                      --------------------------
                                                           Kenneth Whipple
                                                      Chairman of the Board and
                                                       Chief Executive Officer