In the case of Flanagan et al. v. United States (1983), the U.S Supreme Court ruled that orders disqualifying counsel in a criminal case are not immediately appealable under 28 U.S.C Section 1291, which allows appeals from all final decisions by district courts except where direct review may be had in the Supreme Court. The court held that such an order does not meet the criteria for being considered as a "final decision". It reasoned that allowing immediate appeal would disrupt and delay ongoing proceedings, contrary to Congress's intent when it enacted Section 1291. The court also noted there were other ways to protect defendants' rights without interrupting trials, including seeking writs of mandamus or prohibition or raising objections after conviction on appeal.

In the dissenting opinion for Flanagan et al. v. United States, Justice Stevens argued that the Court's decision to allow immediate appeal of disqualification orders could potentially lead to unnecessary delays in criminal proceedings and undermine judicial efficiency. He contended that such a ruling would encourage defendants to use disqualification motions as a tactic for delay or disruption, thereby undermining the smooth functioning of the justice system. Furthermore, he expressed concern about expanding appellate jurisdiction beyond its traditional boundaries without clear congressional authorization or compelling justification from policy considerations. In his view, it was not sufficient reason to permit interlocutory appeals simply because an order may have an important impact on litigation; rather there should be evidence showing that delaying review until after final judgment would cause irreparable harm.