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Tammera R. Diehm

p (612) 604-6658   f (612) 604-6958 
William Mitchell College of Law, J.D., summa cum laude, 2003
Augsburg College, B.A, Political Science & Urban Studies, summa cum laude, 1993
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Tammera R. Diehm is a shareholder at Winthrop & Weinstine with extensive expertise in complex real estate and leasing matters. In her practice, Tami has represented local and national clients of all types and sizes in real estate transactions involving multiple levels of government approvals, environmental challenges and various forms of public and private financing. Tami regularly appears before local governments and regulatory agencies on behalf of clients seeking land use and permitting approvals, and works with clients to find creative solutions to complex projects.  Tami served as city attorney for a first ring suburb for eight years, and served three terms as an elected city council member for Columbia Heights, where she lives.  Her knowledge of both the legal and political aspects of land use and zoning issues bring a fresh and creative perspective to real estate development projects.  

In addition, Tami helps lead a multi-disciplinary team of lawyers who provide full service representation to gas and convenience store owners and fuel distributors. The team provides legal expertise and practical advice in all areas affecting people in this industry including real estate, land use, zoning, leasing, environmental, finance, tax, employment, corporate, intellectual property, succession planning, regulatory and M&A services and litigation. From day-to-day operational issues to unique and specialized matters such as large acquisitions, new development and asset divestiture, Tami and her team truly cover the waterfront to provide full service to these clients.

Along with land use, environmental and real estate development, Tami has experience representing both for-profit and tax-exempt organizations on a variety of issues, including formation, tax and general governance. She has assisted organizations with compliance matters involving the Internal Revenue Service, the Minnesota Attorney General’s office, the Minnesota Campaign Finance and Public Disclosure Board and the Federal Election Commission. Tami provides general counsel services to a number of for-profit and non-profit clients of varying sizes throughout the Twin Cities area, and is a frequent speaker on issues related to lobbying and corporate political involvement.    

Prior to joining the firm, Tami served as a judicial extern for Federal Magistrate Judge Jonathan Lebedoff (2003) and clerked for the Honorable Russell A. Anderson, Minnesota Supreme Court, 2003-2004. In addition to having served on the City Council, Tami was a member of the Columbia Heights Economic Development Authority and was Chair of the Housing and Redevelopment Authority. Tami served as an appointed member of the Metropolitan Council’s Land Use Advisory Committee and served as a policy member of the Minneapolis Nicollet-Central Policy Advisory Committee. Tami is a member of the Board of Directors of the firm, and has been recognized by her peers with honors including as a Rising Star, 2007-2012; Minnesota Super Lawyer, 2015-2017; inclusion in The Best Lawyers in America© in Municipal Law and Land Use Zoning, 2010-2018, and Real Estate Law in 2018; a Forty Under Forty honoree; the MSBA North Star Lawyer recognition, 2012-2017; and among the "Top Women in Finance" by Finance & Commerce, 2014.

Bar Admissions

Minnesota, 2003
U.S. District Court for the District of Minnesota, 2010


Articles & Presentations

Campaign Finance

Qtd. Mont, Joe. "In A Heated Campaign Season, Don't Forget About Compliance." Compliance Week. 20 Sept. 2016.

Qtd. "Political Activities May Need Policy Update as Fall Elections Loom." Report on Medicare Compliance. Vol. 23, Number 24. 27 June 2016. Reprinted in AIS Health. 15 July 2016.

Qtd. "Political Activities May Need Policy Update as Fall Elections Loom." Report on Medicare Compliance. Vol. 23, Number 24. 27 June 2016.

Speaker. "There's an Election Coming What Corporate Compliance Officers Need to Know About Political Activity." Society of Corporate Compliance and Ethics. 14 June 2016.

Co-Presenter. Matrix Capital Markets Group Luncheon. In-House Presentation. 4 May, 2016.

Speaker. " There's an Election Coming! What Business Counsel Need to Know About Political Law." Minnesota CLE. 3 May 2016.

Speaker. "Getting Engaged Without Breaking the Law." Minnesota Business Partnership. 20 Aug. 2014.

Qtd. Gallegos, Anna. "McCutcheon V FEC: Narrow Ruling Prompts Larger Campaign Donation Debate." LXBN. 7 April 2014.

Presenter. "Corporations Have First Amendment Rights Too: An Introduction to How Corporations can be Active in American Politics." 15 Jun. 2012.

Speaker. "There's an Election Coming! What Corporate Counsel Need to Know About Political Law." Hennepin County Bar Association. Live Webcast. 19 Jan. 2012.

Panelist. "Lobbying by Non-Profit Clients: Navigating Federal and State Regulations." Strafford Publications. Webinar. 19 Oct. 2011.

Co-author. "Minnesota Responds to Citizens United." Newsletter of the ABA Business Law Section Committee on Government Affairs Practice. Vol. 1, Issue 3. (Summer 2010). Republished: ABA Business Law Section's Business Law Today. 28 Oct. 2010.

Co-author. "The Hatch Act: It's Not Just for Federal Employees Anymore." Newsletter of the ABA Business Law Section Committee on Government Affairs Practice 1 (Fall 2009). Republished: Newsletter of the ABA Business Law Section. Mar. 2010.

Speaker. "The Basics – Laws Governing Candidates and Campaign Finance." How to Run for Office. Minnesota Association of Realtors’ Conference Room, Minneapolis. 20 Aug. 2009.

Real Estate
Co-Presenter. "Representing the Ongoing Business Deskbook Series: Negotiating Commercial Leases for Small Businesses." Minnesota CLE. Webcast. 7 February 2017.
Co-Presenter. NAIOP Awards of Excellence. Commercial Real Estate Development Association. 22 September 2016.

Co-Presenter. "Important Aspects of Commercial Real Estate Sale, Purchase, and Development." Minnesota CLE. 28 July 2016.

Presenter. "Minor and Major Subdivisions - Methods, Process and Considerations." 2015 Real Estate Institute. 22 October 2015.

Panelist. "Brownfield Liability & Risk Assessment." Minnesota Real Estate Journal 2015 Brownfields Summit. 12 June 2015.

Co-Presenter. "Ongoing Business Deskbook: Negotiating Commercial Leases for Small Businesses." Minnesota CLE. 12 May 2015.

Qtd. in Heilman, Dan. "Read the Fine Print: How to Avoid Legal Hassles Between Office Tenants, Landlords. Finance and Commerce. 9 Aug. 2012.

Speaker. "Unlawful Detainers and Collection Issues: Practical Suggestions for Dealing with Tenant Problems." Minnesota Continuing Real Estate Education. Jun. 2012.

Co-Author. "Negotiating Commercial Leases for Small Business." Minnesota CLE Deskbook for Representing the Ongoing Business. Oct. 2011.

Co-Presenter. "Business Leases and the Attorney's Lease Analysis Letter." Minnesota CLE. 29 Oct. 2011.

Speaker. “Developing the Next Killer App: Who Will Test the Prototype – Development Finance.” Public Finance Seminar, Ehlers. Northland Inn, Brooklyn Park, MN. 4 Feb. 2011.

Presenter. "Getting Your Real Estate Development Through City Hall: Practical and Ethical Considerations of the Development Approval Process.” Hennepin County Bar Association CLE, Minneapolis, MN. Jan. 2008. 

Presenter. “The Legal Environment of Investment Real Estate.” University of St. Thomas Mini Masters Series. University of St. Thomas, Minneapolis, MN. Nov. 2007.

Presenter. "Dealing With Decision Makers: Practical and Ethical Considerations of the Development Approval Process." The Development Approval Process in Minnesota. Lorman CLE, Bloomington and St. Paul, MN. Apr. 2007.

Presenter. “Brownfield Redevelopment: Columbia Heights Industrial Park.” 2006 Ehlers Public Finance Seminar. Brooklyn Center, MN. Feb. 2006.

Author. "When Representing Clients Before City Hall, Some Attorneys are Required to Register as Lobbyists.” Minnesota Lawyer. 14 Aug. 2006: 21.


Presenter. "Creating and Operating a Tax Exempt Entity." National Business Aviation Association Regional Leadership Roundtable. 14 May 2015.

Qtd. in Swedberg, Jamie. "Pro Business: Pro bono work by local law firms helps both small business and nonprofit organizations." Twin Cities Business. Feb. 2008: 99-104.

"Spotlight on Tammera (Ericson) Diehm." Inside Augsburg. 18 May 2007.

Author. “Appellate Tips From a Law Clerk's Perspective.” Ramsey County Barrister. Feb. 2005.


Press Releases

January 10, 2018
Winthrop & Weinstine, P.A., Announces New Board of Directors

August 15, 2017
Twenty-Nine Winthrop & Weinstine Attorneys Named to 2018 “Best Lawyers In America” List

July 05, 2017
Thirty Winthrop & Weinstine Attorneys Named to Super Lawyers List

May 23, 2017
Winthrop & Weinstine Attorneys Recognized for 2016 Pro Bono Service

August 15, 2016
Twenty-Six Winthrop & Weinstine Attorneys Named to 2017 “Best Lawyers In America” List

July 05, 2016
Forty-Six Winthrop & Weinstine Attorneys Named as Super Lawyers and Rising Stars

May 16, 2016
Winthrop & Weinstine Attorneys Recognized for 2015 Pro Bono Service

November 03, 2015
Winthrop & Weinstine Represents Stop-a-Sec In Successful Sale of Eight Stores

August 17, 2015
Twenty-Five Winthrop & Weinstine Attorneys Named to 2016 “Best Lawyers In America” List

July 07, 2015
Twenty-Nine Winthrop & Weinstine Attorneys Named to Super Lawyers List

June 04, 2015
Winthrop & Weinstine Attorneys Recognized for 2014 Pro Bono Service

March 12, 2015
Winthrop & Weinstine Represents Erickson Oil Products and Team Investments LLC on $85 Million Sale

September 25, 2014
Tami Diehm Receives Finance & Commerce’s Top Women in Finance Honors

August 18, 2014
Twenty-One Winthrop & Weinstine Attorneys Named to 2015 “Best Lawyers In America” List

May 15, 2014
Winthrop & Weinstine Attorneys Recognized for 2013 Pro Bono Service

October 11, 2013
Winthrop & Weinstine Represents Dominium in Pillsbury A-Mill Project

August 15, 2013
Twenty-One Winthrop & Weinstine Attorneys Named to 2014 “Best Lawyers In America©” List

June 19, 2013
Minnesota State Bar Association Recognizes Winthrop & Weinstine Attorneys for 2012 Pro Bono Service

September 19, 2012
Twenty Two-Attorneys from Winthrop & Weinstine Named to “Best Lawyers in America” List

July 09, 2012
Thirteen Winthrop & Weinstine Attorneys on Super Lawyers®-Rising Stars List 2012

September 13, 2011
Seventeen Lawyers Listed in The Best Lawyers in America®

July 12, 2011
Thirteen Winthrop & Weinstine Attorneys Selected for Inclusion in Rising Stars

December 21, 2010
Winthrop & Weinstine Celebrates This Holiday Season with the Help of Local Talent

November 22, 2010
Sixteen Shareholders Named to Best Lawyers in America

Client Alerts

Honors & Awards
  • "Top Women in Finance," Finance & Commerce, 2014
  • MSBA North Star Lawyer for Pro Bono Service, 2012-2017
  • The Best Lawyers in America©
    • Minneapolis Lawyer of the Year: Municipal Law, 2017
    • Municipal Law, 2010-2018
    • Land Use and Zoning Law, 2013-2018
    • Real Estate Law, 2018
  • "40 Under Forty" Honoree, Minneapolis/St. Paul Business Journal, 2010
  • Minnesota Rising Stars, 2007-2012
  • Minnesota Super Lawyers®, 2015-2017
  • “Up & Coming Attorney,” Minnesota Lawyer, 2006
  • Augsburg College First Decade Award, October 2003
  • William Mitchell Student of Merit Award, June 2003
  • Assistant Editor, William Mitchell Law Review, 2002-2003
  • Burton Brief Award, 2001

Professional Associations & Memberships
  • American Bar Association
  • Minnesota State Bar Association
  • Anoka County Bar Association
  • Minnesota Commercial Real Estate Women (MNCREW)
  • NAIOP (Commercial Real Estate Development Association)
  • Minnesota Petroleum Marketers Association (MPMA)
  • National Association of Convenience Stores (NACS)
  • Minnesota Service Station & Convenience Store Association (MSSA)
  • Society of Independent Gasoline Marketers of America (SIGMA)

Elected Offices & Appointments

  • Board of Directors, Winthrop & Weinstine, 2018-present
  • Board of Directors, Aeon, 2016-present
  • LegalCORPS
    • Board of Directors, 2011-present
    • President, 2013-2015
  • City of Columbia Heights
    • City Council, 2003-2014
      • President, 2007-2014
    • Planning and Zoning Commission, 2000-2002
    • Charter Commission, 1998-2002
      • President, 2000-2002
    • Economic Development Authority, 2003-2014
    • Housing and Redevelopment Authority, 2003-2016
      • Chair, 2006-2016
  • Member, Metropolitan Council Land Use Advisory Committee, 2007-2014
  • Member, Nicollet-Central Policy Advisory Committee, 2012-2013
  • Hennepin County Bar Association
    • Chair, Eminent Domain Section Committee, 2017-present
    • Vice Chair, Eminent Domain Section Committee, 2016-2017
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