1
                                                                    EXHIBIT 5(a)



                 [LETTERHEAD OF RICHARDS, LAYTON & FINGER, P.A.]







                                  June 15, 2001





Comerica Capital Trust I
Comerica Incorporated
Comerica Tower at Detroit Center
Detroit, MI 48226

                  Re:      Comerica Capital Trust I

Ladies and Gentlemen:

                  We have acted as special Delaware counsel for Comerica
Incorporated, a Delaware corporation (the "Company"), and Comerica Capital Trust
I, a Delaware business trust (the "Trust"), in connection with the matters set
forth herein. At your request, this opinion is being furnished to you.

                  For purposes of giving the opinions hereinafter set forth, our
examination of documents has been limited to the examination of originals or
copies of the following:

                  (a) The Certificate of Trust of the Trust, dated June 12, 2001
(the "Certificate"), as filed in the office of the Secretary of State of the
State of Delaware (the "Secretary of State") on June 13, 2001;

                  (b) The Declaration of Trust of the Trust, dated as of June
12, 2001, among the Company and the trustees of the Trust named therein;

                  (c) A form of Amended and Restated Declaration of Trust of the
Trust, (including Exhibits A and B thereto) (the "Declaration"), to be entered
into among the Company, the trustees of the Trust named therein, and the
holders, from time to time, of undivided beneficial interests in the assets of
the Trust, attached as an exhibit to the Registration Statement (as defined
below);

                  (d) The Registration Statement on Form S-3 (the "Registration
Statement"), including a prospectus (the "Prospectus"), relating to the
preferred securities of the Trust, representing undivided beneficial interests
in the assets of the Trust (each, a "Preferred Security" and collectively, the
"Preferred Securities"), as proposed to be filed by the Company, the Trust and
others with the Securities and Exchange Commission on or about June 15, 2001;
and

                  (e) A Certificate of Good Standing for the Trust obtained from
the Secretary of State on June 15, 2001.

                  Capitalized terms used herein and not otherwise defined are
used as defined

   2


Comerica Capital Trust I
June 15, 2001
Page 2


in the Declaration.

                  For purposes of this opinion, we have not reviewed any
documents other than the documents listed in paragraphs (a) through (e) above.
In particular, we have not reviewed any document (other than the documents
listed in paragraphs (a) through (e) above) that is referred to in or
incorporated by reference into the documents reviewed by us. We have assumed
that there exists no provision in any document that we have not reviewed that is
inconsistent with the opinions stated herein. We have conducted no independent
factual investigation of our own but rather have relied solely upon the
foregoing documents, the statements and information set forth therein and the
additional matters recited or assumed herein, all of which we have assumed to be
true, complete and accurate in all material respects.

                  With respect to all documents examined by us, we have assumed
(i) the authenticity of all documents submitted to us as authentic originals,
(ii) the conformity with the originals of all documents submitted to us as
copies or forms, and (iii) the genuineness of all signatures.

                  For purposes of this opinion, we have assumed (i) that the
Declaration and the Certificate are in full force and effect and have not been
amended, (ii) except to the extent provided in paragraph 1 below, that each of
the parties to the documents examined by us has been duly created, organized or
formed, as the case may be, and is validly existing in good standing under the
laws of the jurisdiction governing its creation, organization or formation,
(iii) the legal capacity of natural persons who are signatories to the documents
examined by us, (iv) that each of the parties to the documents examined by us
has the power and authority to execute and deliver, and to perform its
obligations under, such documents, (v) that each of the parties to the documents
examined by us has duly authorized, executed and delivered such documents, (vi)
the receipt by each Person to whom a Preferred Security is to be issued by the
Trust (collectively, the "Preferred Security Holders") of a Capital Security
Certificate for such Preferred Security and the payment for the Preferred
Security acquired by it, in accordance with the Declaration and the Registration
Statement, and (vii) that the Preferred Securities are issued and sold to the
Preferred Security Holders in accordance with the Declaration and the
Registration Statement. We have not participated in the preparation of the
Registration Statement and assume no responsibility for its contents.

                  This opinion is limited to the laws of the State of Delaware
(excluding the securities laws of the State of Delaware), and we have not
considered and express no opinion on the laws of any other jurisdiction,
including federal laws and rules and regulations relating thereto. Our opinions
are rendered only with respect to Delaware laws and rules, regulations and
orders thereunder that are currently in effect.

                  Based upon the foregoing, and upon our examination of such
questions of law and statutes of the State of Delaware as we have considered
necessary or appropriate, and subject to the assumptions, qualifications,
limitations and exceptions set forth herein, we are of the opinion that:

                  1. The Trust has been duly created and is validly existing in
good standing as a business trust under the Business Trust Act.

                  2. The Preferred Securities will be duly authorized and will
represent valid and, subject to the qualifications set forth in paragraph 3
below, fully paid and nonassessable undivided beneficial interests in the assets
of the Trust.

                  3. The Preferred Security Holders, as beneficial owners of the
Trust,

   3


Comerica Capital Trust I
June 15, 2001
Page 3



will be entitled to the same limitation of personal liability extended to
stockholders of private corporations for profit organized under the General
Corporation Law of the State of Delaware. We note that the Preferred Security
Holders may be obligated to make payments as set forth in the Declaration.

                  We consent to the filing of this opinion with the Securities
and Exchange Commission as an exhibit to the Registration Statement. In
addition, we hereby consent to the use of our name under the heading "Legal
Opinions" in the Prospectus. In giving the foregoing consents, we do not thereby
admit that we come within the category of Persons whose consent is required
under Section 7 of the Securities Act of 1933, as amended, or the rules and
regulations of the Securities and Exchange Commission thereunder. Except as
stated above, without our prior written consent, this opinion may not be
furnished or quoted to, or relied upon by, any other Person for any purpose.

                                             Very truly yours,



                                             /s/ Richards, Layton & Finger, P.A.

BJK/MSC