Mark W. DeLaquil

Partner

Washington, D.C.
T +1.202.861.1527
F +1.202.861.1783

Overview

Mark DeLaquil is an experienced advocate who focuses on appellate practice, complex environmental and regulatory proceedings, and political law.

Mark has been recognized by Chambers USA for environmental litigation (2015), has been named one of Law360's "Top 5 Environmental Attorneys Under the Age of 40," and has been designated as a Super Lawyers “Rising Star” (2014). 

Select Experience

Environmental Regulatory Proceedings and Litigation
  • Represented state and private clients in Clean Air Act administrative proceedings and litigation, including preparing comments on proposed actions and contesting them in courts of appeals. Has extensive experience in actions concerning climate change, air quality standards, emission standards, preconstruction and operating permits, and state implementation plans.
Appellate Litigation
  • Represented parties in appeals throughout the United States and argued numerous appeals in the Second, Seventh, Eighth, Ninth, and District of Columbia Circuits.
Political Law
  • Represented clients in a full array of campaign finance matters, from counseling compliance to successfully challenging the enforcement of state campaign finance law.  
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Experience

Environmental Regulatory Proceedings and Litigation
  • Represented state and private clients in Clean Air Act administrative proceedings and litigation, including preparing comments on proposed actions and contesting them in courts of appeals. Has extensive experience in actions concerning climate change, air quality standards, emission standards, preconstruction and operating permits, and state implementation plans.
    • Represented a manufacturing company in an administrative proceeding defending the validity of its preconstruction and operating air permit.
    • Counseled a leading electric utility on Clean Air Act compliance strategy and the potential legal implications of climate change for the U.S. industry.
Appellate Litigation
  • Represented parties in appeals throughout the United States and argued numerous appeals in the Second, Seventh, Eighth, Ninth, and District of Columbia Circuits.
    • Argued an appeal on behalf of a steel manufacturer in support of affirmance of a decision dismissing a citizen suit alleging violations of the Clean Air Act preconstruction permitting program.
    • Argued an appeal on behalf of a nonprofit organization in support of affirmance of a preliminary injunction stopping a criminal investigation.
    • Argued an appeal in support of the reversal of a decision confirming labor arbitration awards.
    • Argued a challenge to a decision revising approval of a state implementation plan arising out of the Clean Air Act greenhouse gas regulation.  
  • Represented parties and amici curiae in proceedings before the U.S. Supreme Court and nearly all of the U.S. Courts of Appeals. 
    • Represented an amicus group composed of all former Secretaries of Defense and members of the Joint Chiefs of Staff in an appeal of a decision denying qualified immunity to former Secretary of Defense Donald Rumsfeld, helping secure a rehearing en banc.
    • Represented an amicus group of law professors before the U.S. Supreme Court supporting a petition for certiorari and merits proceedings in a global climate change public nuisance suit against electric utilities.
Political Law
  • Represented clients in a full array of campaign finance matters, from counseling compliance to successfully challenging the enforcement of state campaign finance law.
    • Served as lead trial counsel in an action obtaining permanent injunction barring the enforcement of state law binding delegates to national party conventions to the results of a presidential preference primary.
    • Obtained a preliminary injunction barring the enforcement of a state law requiring certain social welfare organizations to register as political committees.
    • Obtained a preliminary injunction barring the enforcement of a state law barring coordination between candidates and unaffiliated organizations concerning issues advocacy.
    • Argued an appeal seeking affirmance of a decision enjoining a criminal investigation into alleged state campaign finance violations.
    • Has counseled businesses and nonprofit entities on compliance campaign finance and ethics law requirements.

Recognitions and Memberships

Recognitions

  • Chambers USA: Litigation: Environment in the District of Columbia (2015 to 2017)
  • Law360 "Rising Star" in Environmental (2016)
  • Law360 "Top 5 Environmental Attorneys Under the Age of 40"
  • Martindale-Hubbell: AV Preeminent
  • Washington, D.C., Super Lawyers "Rising Star" (2014)

Memberships

  • ALI-ABA: Faculty of Global Warming: "Climate Change and the Law"

Industries

Admissions

  • U.S. Court of Appeals, Federal Circuit, 2017
  • U.S. Court of Appeals, Second Circuit, 2013
  • U.S. Court of Appeals, Fourth Circuit, 2004
  • U.S. Court of Appeals, Fifth Circuit, 2009
  • U.S. Court of Appeals, Seventh Circuit, 2006
  • U.S. Court of Appeals, Eighth Circuit, 2015
  • U.S. Court of Appeals, Ninth Circuit, 2013
  • U.S. District Court, Eastern District of Wisconsin, 2014
  • U.S. District Court, District of Columbia, 2006
  • U.S. District Court, Eastern District of Virginia, 2005
  • U.S. Bankruptcy Court, Eastern District of Virginia, 2006
  • U.S. Court of Appeals, District of Columbia Circuit, 2006
  • District of Columbia, 2005
  • Virginia, 2004

Education

  • J.D., Harvard Law School, 2004, cum laude
  • B.A., University of Florida, 2001, magna cum laude