Tyson Arbuthnot
Gayle M. Athanacio
Merri A. Baldwin
Ann M. Blessing
Robert J. Breakstone
Dennis J. Callahan
Thomas H. Carlson
Jeffery M. Chiow
Robert C. Goodman
Lucas T. Hanback
John G. Heller
Dennis C. Huie
Suhani Kamdar
Lauren B. Kramer
Sharon L. Larkin
S. Amber Lee
Mark J. Linderman
James Robert Maxwell
Joseph C. McGowan
Patricia A. Meagher
Robert S. Metzger
Alexis J. Morris
Nicholas T. Niiro
Roland Nikles
Neil H. O'Donnell
Robert M. Osier
Dean D. Paik
Katherine L. Pohl
Sharon Ongerth Rossi
Aaron M. Scolari
D. Kevin Shipp
Aaron P. Silberman
Renée D. Wasserman
Alan J. Wilhelmy
Virginia K. Young
Oliya S. Zamaray
Paul M. Zieff

Dennis J. Callahan
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Areas of Practice

Mr. Callahan is a member of the firm’s Government Contracts and Complex Commercial Litigation Practice Groups.

Professional Qualifications

Mr. Callahan represents government contractors on a broad range of litigation matters, including bid protests and contract claims at the federal, state and local levels and prime/subcontractor disputes in state and federal court, arbitration and mediation. Mr. Callahan also counsels government contractors and grantees regarding their compliance with contract and legal requirements, accounting standards and audit practices. He has extensive counseling and dispute experience involving cooperative agreements, teaming agreements and other costshare and workshare agreements.

Mr. Callahan also has significant experience drafting technical documents and correspondence to government agencies designed to avoid disputes involving highly regulated industries, including segments of the telecommunications, energy, and transportation industries.

Mr. Callahan frequently contributes to bar publications and scholarly journals.  Among other publications, his articles have appeared in the William & Mary Law Review, Cardozo Law Review, The Government Contractor, Legal Times (Washington), New York Law Journal, and The Federal Lawyer.


Hon. D. Brooks Smith, United States Court of Appeals for the Third Circuit,
2004-05 Term

Hon. Jackson L. Kiser, United States District Court for the Western District of Virginia, 2003-04 Term


J.D., William & Mary Law School, 2003

M.B.A., William & Mary Graduate School of Business, 2003

B.A., University of New Hampshire, 1989

Bar Admissions
California - 2007
New York - 2004
District of Columbia - 2012

Complex Commercial Litigation
Government Contracts

Recent Publications and Public Speaking

State False Claims Acts: A Practitioner's Guide to the False Claims Acts of the Various States, ABA Publishing, 2014 (co-authored) ABA Webstore.

2013 Government Contract Law Decision of the Federal Circuit, 63 American University Law Review 1307 (2014), (PDF) co-authored

Hoping for Summary Judgment on California False Claims? Au Contreras, AGC California Legal Brief, Mar. 2014, (PDF) co-authored

Government Shutdown Q & A: Navigating in Uncharted Waters, a CLE webinar for the Public Contracting Institute, October 15, 2013 (slide show)

If Budget Sequestration Trims Your Contract: What Contractors Need to Know About Partial Terminations and Deductive Changes (PDF) RJO Government Contracts Update, September 2012, co-authored

What Contractors Need to Know About Changes to State False Claims Acts, webinar for TechAmerica, September 11, 2012 (PDF) (co-presented) materials

Contractors Should Watch Out for Big Changes Coming to the California False Claims Act, California Constructor, by AGC California, September/ October 2012 (PDF) (co-authored)

Ninth Circuit Holds That False Estimates in Federal Bids Are Actionable Under the False Claims Act, RJO Government Contracts Update, August 2012 (PDF) (co-authored)

States Broadening Their False Claims Acts in Response to Federal Incentives, RJO Government Contracts Update, July 2012 (PDF) (co-authored)

"Preparing for Strengthened States False Claims Acts," ABA State & Local Procurement Division, June 22, 2012

A-12 Saga Continues
The Government Contractor, Vol. 52, No. 45, December 8, 2010
by N. O'Donnell and
D. Callahan


Robert Dollar Building
311 California Street, 10th Floor
San Francisco, CA 94104
Phone: 415.956.2828
Fax: 415.956.6457
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