Interstate and International Custody and Support Jurisdiction: The Contests That Void Orders

Katy Mickelson, Equity Partner | Beermann LLP

Katy Mickelson represents clients in family law matters that cross borders, including divorce and parentage cases in which the parties, the assets, or the children are located in more than one jurisdiction, and prenuptial agreements between parties of different nationalities where the governing country’s law must be resolved before drafting begins. She is a Fellow of the International Academy of Family Lawyers and an Equity Partner at Beermann LLP in Chicago, where she has practiced family law for more than two decades.

• Education & Credentials

Kathryn Homburger Mickelson earned her Juris Doctor from Chicago-Kent College of Law at the Illinois Institute of Technology in 2005 and her Bachelor of Arts in Sociology from the University of Michigan in 1995. She is a certified mediator and has been admitted to practice law in Illinois since 2005 and before the U.S. District Court for the Northern District of Illinois since 2006.

• Recognition & Leadership

Katy is a Fellow of the International Academy of Family Lawyers, a group of leading family law practitioners worldwide, and a Fellow of the American Academy of Matrimonial Lawyers, where she sits on the Illinois Chapter Board. She has been named to the Lawdragon 500 Leading U.S. Family Lawyers and recognized by Best Lawyers (2026), by Leading Lawyers Magazine as a Leading Family Law Attorney, by Super Lawyers as a Top-Rated Family Law Attorney, and by Crain’s Chicago Business among its Most Notable Women Attorneys. She also holds an Avvo Rating of 10.0.

• Professional Involvement

Katy has served for three years on the faculty of the National Family Law Trial Institute, teaching advanced trial technique, and will join the AAML faculty in fall 2026 at the Institute for Family Law Associates, the Academy’s national program for newer attorneys. The presiding judge of Cook County’s Domestic Relations Division selected her to demonstrate trial technique at the Division’s CLE seminar, and she has presented mock-trial work with the American Academy of Matrimonial Lawyers. She formerly co-chaired the Domestic Relations Roundtable of the Women’s Bar Association of Illinois, a CLE event for family law attorneys and judges.

She is an active member of the Illinois State Bar Association, contributing to its legal education and ethics committees, and of the Chicago Bar Association. Outside the bar, she leads a ProVisors group, participates in the Economic Club of Chicago, serves on the Board of Trustees of Court Theatre, and is Past President of the Chicago Council of the American Writers Museum.

• Experience

Alongside her multi-jurisdiction divorce, parentage, and prenuptial work, Katy handles relocation of a child, non-parent visitation, and assisted reproduction technology matters.

Across a career spanning thousands of cases, she has represented clients in pre- and post-decree divorce, parentage matters, prenuptial and post-nuptial agreements, and domestic violence cases. Her clients include business owners, executives, professional athletes, and high-net-worth families with companies, trusts, and estates at stake. She is the only woman at Beermann LLP to have risen from law clerk to equity partner.

Michael M. Shemkus, Founding Member | Shemkus Family Law, P.A.

Michael M. Shemkus has presented on the Uniform Child Custody Jurisdiction and Enforcement Act for Halfmoon Education, Inc., and his family law practice encompasses custody and support matters, including at the appellate level. He is the founding member of Shemkus Family Law, P.A. in Naples, Florida, practices family law exclusively, and is Board Certified in Marital and Family Law by The Florida Bar.

• Education & Credentials

Michael earned his J.D. from the University of Illinois College of Law in 2013 and his B.A. in Economics from Lewis & Clark College in 2008, where he was named to the Dean’s List. He was admitted to the Illinois bar in 2013 and the Florida bar in 2014, and is also admitted to the U.S. District Court for the Central District of Illinois. The Florida Bar board certified him in Marital and Family Law in 2023.

• Recognition & Leadership

Michael has been recognized by SuperLawyers (2025–2026), served as a Super Lawyers Blue Ribbon Panelist in Family Law (2026), and was named among Top Lawyers 2025. Earlier honors include SuperLawyers Rising Star (2022–2023), the Florida Bar Family Law Section Rising Star Award, and the Collier County Bar Association Family Law Section Chair Award. He chaired the Collier County Bar Association’s Family Law Section in 2019–2020 after serving as its Vice Chair in 2018–2019.

• Professional Involvement

Michael’s presentations include “Uniform Child Custody Jurisdiction and Enforcement Act” and “Strange Developments in Recent Case Law” for Halfmoon Education, Inc.; “The Real Impact of the Equal TimeSharing Presumption,” “Leveling the Playing Field in a Gray Divorce,” and a two-part series on the Alimony Reform Act for the Association of Family Law Professionals; and practice-and-procedure programs on depositions and pleadings for the Collier County Bar Association Family Law Section. He has moderated the judicial panel at the Charlotte County Family Law Convention in 2025 and 2026.

He has written for Adverse Witness, The Family Law Commentator, ActionLine, and ISBA section newsletters on subjects including the equal time-sharing presumption, pregnancy in dissolution proceedings, private judges in family law, and invasion of capital assets in determining alimony. His memberships include the Florida State Bar Association (2014–present), the Illinois State Bar Association (2013–present), the Collier County Bar Association (2017–present), the Michael R. N. McDonnell American Inn of Court (2017–2018 season), and the Peoria County Bar Association (2013–2016).

• Experience

Michael’s practice covers all areas of family law and divorce, including custody, support, domestic violence, and complex property allocation, and his firm’s practice areas include interstate child custody and child support modifications. His published appellate opinions include Frazier v. Frazier (Fla. 6th DCA 2024), Formica v. Vergo, 2024 WL 1635701 (Fla. 6th DCA 2024), Reiser v. Reiser, 363 So.3d 1059 (Fla. 6th DCA 2022), Gillespie v. Holdsworth, 333 So.3d 278 (Fla. 2d DCA 2022), Gillespie v. Minning, 330 So.3d 981 (Fla. 2d DCA 2021), and Marzucco v. Maconi, 254 So.3d 928 (Fla. 2d DCA 2018).

Before founding his firm, he was a Partner at Long, Murphy & Shemkus, P.A. (2023–2025) and an associate at Long, Murphy & Zung, P.A. and Long & Murphy, P.A. from 2017, and began his career as an associate at Kavanagh, Scully, Sudow, White & Frederick, P.C. (2013–2016).

SESSION 1 – Litigating UCCJEA Home State and Emergency Jurisdiction Contest | Michael M. Shemkus | 2:30pm – 3:30pm

This session examines the jurisdictional rules under the Uniform Child Custody Jurisdiction and Enforcement Act (UCCJEA) that determine whether a custody order is valid or void, focusing on home state calculation, exclusive continuing jurisdiction, and temporary emergency jurisdiction. Attorneys will learn how to identify and litigate jurisdictional defects—including when defects render orders void versus voidable—and how to navigate the transition from emergency to permanent jurisdiction. Participants leave with practical tools to challenge or defend custody jurisdiction at the trial and appellate levels, including in cases involving wrongful removal and Hague Convention overlap.

BREAK | 3:30pm – 3:40pm

SESSION 2 – Interstate and International Support Orders: Registration, Enforcement, and the Defenses That Disappear | Kathryn Homburger Mickelson | 3:40pm – 4:40pm

This session picks up where jurisdictional litigation ends by examining the next stage of an interstate or international family-law dispute: recognizing, registering, enforcing, or modifying an existing support order across state and national borders. Attorneys will examine UIFSA’s registration framework, the deadlines for contesting registration, the limited defenses available to an obligor, and the consequences of failing to timely object. The session will also address foreign support orders, including the distinction between Hague Convention and non-Convention matters, and how choice-of-law and continuing-jurisdiction principles affect enforcement, arrears, interest, and modification. Particular attention will be given to coordinating registration and enforcement with the underlying custody and jurisdiction issues addressed in Session 1.