WASHINGTON – Sheldon Cohen, 84, is old enough to remember watching the U.S. Supreme Court building under construction more than 75 years ago. Mortimer Caplin, 95, still swims daily and reports to work at the law firm he helped found more than 45 years ago, Caplin & Drysdale.

The two elder statesmen of the tax law bar, both former Internal Revenue Service commissioners, would be entitled to sit on the sidelines of one of the biggest political and legal battles of the new century. Instead, the two have joined in a brief that could help stall litigation against the Obama health care reform law until 2014 or later.