Several federal appeals courts have ruled against the constitutionality of the recess appointments, which included posts on the National Labor Relations Board, as well as the initial insertion of Richard Cordray as the Consumer Financial Protection Bureau chief. The administration said the appointments were valid but Senate Republicans said they weren't because the chamber convened pro forma every three days.
While Cordray eventually was confirmed, Obama agreed to replace the questionable NLRB nominees.
The senators' brief was filed in National Labor Relations Board vs. Noel Canning, et al., which raises questions concerning the constitutionality of Obama's recess appointments.
The brief, filed Monday, makes many of the same arguments made by Senate Republicans at the D.C. Circuit Court of Appeals, Roll Call reported.
"Last year, the president made an unprecedented power grab by placing political allies at a powerful federal agency while the Senate was meeting regularly and without even trying to obtain its advice and consent," Senate Republican Leader Mitch McConnell said in a statement announcing the brief.