Two years after leaving the U.S. solicitor general’s office to head the appellate practice at Arnold & Porter, Lisa Blatt continues to leave her mark on the U.S. Supreme Court.

In December, Blatt argued her 29th case, breaking the record for the most cases argued before the high court by any living woman.

The 29th case, Henderson v. Shinseki, has resonated with her. Arguing on behalf of David Henderson, a veteran, and later his widow, who was denied disability benefits because he missed a filing deadline, Blatt said it was “one of those cases you put your heart and soul into.”

In March, the Supreme Court ruled that filing deadlines were not jurisdictional, meaning courts can have flexibility considering cases like Henderson’s in the future. “There are literally hundreds of cases where the veteran is too sick, or they miss a deadline because they file the wrong form,” she said.

Longtime friend David Frederick, a partner at Kellogg, Huber, Hansen, Todd, Evans & Figel, said Blatt’s success speaks to “her fascination with untangling the puzzles presented in Supreme Court cases.”

“She has a great ability to get to the nub of an issue and to focus on what’s most important,” Frederick said.

Blatt said that while she’ll always enjoy arguing before the high court, she’s also thriving on the flexibility that being in private practice offers. From taking on more pro bono work to representing pharmaceutical companies in complex commercial litigation, she said, “I still have the same attitude: Treat every case like it’s a Supreme Court argument.” — Zoe Tillman