Expert on the American presidency and presidential powers, legislative redistricting, campaign finance reform, election law and administration and defense policy
- Presidency and presidential power
- Election administration and redistricting
- Campaign finance
- Defense policy
- Australian politics and elections
- Author of Presidential Leadership: Politics and Policy (10th edition, 2018), with George C. Edwards, III and Stephen J. Wayne
- Expert witness in Gill v. Whitford (WI legislative redistricting case, currently at the U.S. Supreme Court).
- Inaugural Fulbright-ANU Distinguished Chair of Political Science, Australian National University (Canberra, ACT), 2006
- 2002 Neustadt Award for best book on the presidency, "With the Stroke of a Pen: Executive Orders and Presidential Power"
- 2006 Alliant Underkofler Excellence in Teaching Award, University of Wisconsin System