Mark's law practice occurs at the junction of all three branches of government. In the law-making process, he drafts legislation and ballot measures and also challenges initiative ballot titles and petitions; Campaigns & Elections Magazine has called him "Colorado's best election lawyer, bar none." In the courts, he litigates high profile policy and political matters, using trial strategies that the Denver Business Journal said "emphasize innovation over convention." And before executive branch regulatory agencies and licensing boards, he represents commercial clients including industry leaders in Colorado's limited gaming industry. For these reasons, Law Week Colorado named Mark the state's Best Government Lawyer in a Law Firm.
In re Ballot Title for Initiative 1999-2000 #255, 4 P.3d 485 (Colo. 2000) — Successfully represented advocates of initiative against challenge over adequacy of ballot titles and submission clause
Beauprez v. Avalos, 42 P.3d 642 (Colo. 2002) — Successfully represented City & County of Denver in congressional redistricting litigation
Colorado Education Association v. Rutt, 184 P.3d 65 (Colo. 2008) — Successfully represented teachers'''' association in connection with its exercise of First Amendment rights in campaign context
In re Interogatories Submitted on House Bill 04-1098, 88 P.3d 1196 (Colo. 2004) — Successfully represented Colorado General Assembly over governor''''s use of federal funds
Mesa County Bd. of County Comm’rs v. State, 203 P.3d 519 (Colo. 2009) — Successfully represented State of Colorado and the Governor in defending school financing statutes, in light of constitutional tax limitation provisions.