Top Democratic and Republican lawmakers have jumped into a legal fight over the Internal Revenue Service’s enforcement of a section of the Obama administration’s health care law.

Congressional Democrats who helped draft the Affordable Care Act—including Senate Majority Leader Sen. Harry Reid (D-Nev.) and House Minority Leader Rep. Nancy Pelosi (D-Calif.)—filed an amicus brief Saturday that defends the law in a case pending in the U.S. Court of Appeals for the D.C. Circuit.