Commentators have floated a number of theories under which President Trump could face criminal consequences for his firing of FBI Director James Comey. Under one view, that firing reflected an unlawful attempt to interfere with the ongoing Russia investigation, and an easy obstruction of justice case against Trump could be made. See, e.g., Samuel W. Buell, Open and Shut: The obstruction of justice case against Trump is already a slam dunk, Slate (July 6, 2017). Other scholars have taken a more measured approach and have outlined why an obstruction prosecution would raise some difficult questions. See, e.g., Randall Eliason, Did President Trump Obstruct Justice? A Prosecution Analysis, Sidebars Blog (May 15, 2017) (“[T]his would not be a slam-dunk prosecution.”). See generally Hemel & Posner, Presidential Obstruction of Justice, 106 Cal. L. Rev. — (2018).
It remains unclear whether the President’s decision to fire the FBI Director reflects conduct described in any of the various federal obstruction statutes. However, even if it does, that would not necessarily establish criminal liability. An attempt to criminalize the President for one of his official acts, like the firing of a subordinate, raises constitutional concerns, and President Trump could have a separation of powers defense to any prosecution. (For guidance on the line between official and private acts, see Clinton v. Jones, 520 U.S. 681, 688-96 (1997).) See generally Sai Prakash, Regulating Presidential Powers, 91 Cornell L. Rev. 215, 257 (“Congress does not have a generic power to regulate the President’s powers any more than the President has the generic authority to regulate the exercise of Congress’s legislative powers.”).
Under this potential line of analysis, Congress’s attempt to criminalize an official act of the President would improperly diminish the powers assigned to him by the Constitution. If Congress could, for example, criminalize the President’s veto of a bill, that would place improper limits on the veto power, which is not textually limited by the Constitution. Along the same lines, where the executive power contemplates an “illimitable” power to remove an officer, then a Congressional attempt to criminalize the President’s removal of that officer is itself unconstitutional. (Improper use of the veto power or the executive power would, of course, remain addressable through the impeachment procedures expressly provided in the Constitution.)
A separation of powers theory related to the removal power cannot receive complete analysis in a blog post, and one’s receptiveness to it will depend on her views of the Article II vesting clause, the take care clause, the necessary & proper clause, and other things. Nonetheless, there are at least two often-overlooked cases which are worth discussing and which may help promote informed understanding of the issues. The first case, recently decided by the Texas Court of Criminal Appeals and discussed further below, adopts a separation of powers theory like the one described above, and finds unconstitutional an attempt to criminalize Governor Rick Perry’s exercise of the veto power assigned to him by the Texas Constitution. The second case, Nixon v. Fitzgerald, 457 U.S. 731 (1982), holds that the President cannot be held civilly liable for the corrupt firing of a subordinate and implies (though does not expressly state) that he would be similarly immune from criminal prosecution. Fitzgerald is discussed in a separate post. (See here.)
In Ex parte Perry, 483 S.W.3d 884 (Tex. Crim. App. 2016), the State of Texas argued that Governor Perry’s exercise of a veto violated an “abuse of official capacity” criminal statute. Governor Perry apparently threatened to veto legislation that funded a governmental unit unless the head of that unit first resigned. But the unit head refused to resign, and Governor Perry subsequently vetoed the relevant legislation. The State then brought charges against Perry, arguing that the act of vetoing itself violated the criminal statute. See id. at 901.
The Criminal Court accepted Governor Perry’s argument that the prosecution of him for exercising the veto power violated the separation of powers. It noted that the U.S. Supreme Court, in the Pocket Veto Case, had held that Congress could not “narrow or cut down” the President’s veto power, 279 U.S. 655, 677-78 (1929), and it believed that this principle “applie[d] equally to the governor’s veto in Texas.” 483 S.W.3d at 901. That is, no law could “make the mere act of vetoing legislation a crime.” Id. The abuse of official capacity statute could be violated through other acts, such as through an agreement to take a bribe in exchange for promise to make a veto, but in those circumstances, “the illegal conduct is not the veto; it is the agreement to take money in exchange for the promise.” Id. at 901 n.96.
If the United States Supreme Court adopted, in the removal power context, an approach similar to the one in Ex Parte Perry, Congress could not attach any criminal consequences to President Trump’s firing of James Comey. That firing was made under the executive power assigned by Article II, and Congress cannot make the President’s “mere act of [firing a principal executive officer] a crime.” Instead, criminal consequences would have to attach to other acts, such as accepting a payment from a subject of the investigation in exchange for the promise to fire Comey.
But would the Supreme Court adopt an approach similar to the one in Ex Parte Perry? At times, the Supreme Court has adopted a formalist approach to separation of powers questions, much like the one in Ex Parte Perry. But, with equal frequency, it has adopted a functionalist approach, which avoids bright line rules. See generally Peter L Strauss, Formal and Functional Approaches to Separation-of-Powers Questions–A Foolish Inconsistency?, 72 Cornell L. Rev. 488 (1987). Thus, whether the Supreme Court blessed the attempted criminalization of a President’s official act could very well turn on which side wins the formalist-versus-functionalist debate on the day of decision.
In any event, Ex Parte Perry is not discussed here for its actual legal effect in federal courts. But the case should give pause to those who believe Congress could obviously criminalize the President’s firing of James Comey. Ex Parte Perry suggests, as a predictive matter, that persons with a formalist view of separation of powers issues (like this writer) would find unconstitutional any statute that criminalized a President’s official act. Consequently, in discussing whether President Trump obstructed justice through firing James Comey, commentators would be well advised to take seriously the potential constitutional defenses, at least to the extent they wish to affect scholarly opinions. (The practical significance of the question is probably limited, given the extraordinary hurdles facing the attempted indictment of a sitting President for any act, much less an official one.)
Comments welcome. This post will be updated.
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 In Humphrey’s Executor v. United States, the Supreme Court noted that executive officers are “inherently subject to the exclusive and illimitable power of removal by the Chief Executive, whose subordinate and aid he is.” 295 U.S. 602, 627 (1935) (construing Myers v. United States, 272 U.S. 52 (1926)). The Supreme Court’s jurisprudence generally reveals that the removal power stems from the executive powers assigned by Article II, and that the take care clause reinforces this understanding. See, e.g., Free Enterprise Fund v. Public Co. Accounting Oversight Board., 561 U.S. 477, 492 (2010) (“[T]he executive power include[s] a power to oversee executive officers through removal.”). Cf. also Patricia L. Bellia, PCAOB and the Persistence of the Removal Puzzle, 80 Geo. Wash. L. Rev. 1371 (2012)(acknowledging that the Court in Free Enterprise expressly grounded its holding in the Article II vesting clause, but arguing that the vesting clause theory cannot adequately explain the Court’s holding).
In Myers, the Court observed that the Appointments Clause grants the President the exclusive authority to appoint principal officers, and this further implies that removal powers are executive in nature. See 272 U.S. at 119 (endorsing James Madison’s view that “the power of removal of executive officers [is] incident to the power of appointment” and that this further establishes that “the grant of executive power to the President in the first section of Article II carr[ies] with it the power of removal”), and at 163-64 (“Article II grants to the President the executive power of the Government, i.e., the general administrative control of those executing the laws, including the power of appointment and removal of executive officers — a conclusion confirmed by his obligation to take care that the laws be faithfully executed.”).
The Court has also emphasized that, though the Constitution specifies a limited role for the Senate in the appointments process (via the advice and consent function), the absence of any specified role in the removal process helps confirm that congressional involvement in removal decisions is improper. See id. at 121 (“The power to prevent the removal of an officer who has served under the President is different from the authority to consent to or reject his appointment.”), and at 164 (“[T]he provisions of the second section of Article II, which blend action by the legislative branch, or by part of it, in the work of the executive are limitations to be strictly construed, and not to be extended by implication.”).
 The State of Texas has a bifurcated judicial system, under which the Texas Court of Criminal Appeals operates as the state’s court of last resort for most criminal matters. See Texas Constitution, Art. 5., §§ 4 & 5.
 I thank Twitter user @SeIpsa for bringing this case to my attention. Ex Parte Perry is the only case I know of where prosecutors attempted to charge a government official for the exercise of a constitutionally assigned power. If readers are aware of any others, especially in the federal context, I would appreciate a link or citation to them.
 The Court has not endorsed any Congressional limits on the removal of a principal executive officer, that is, officers appointed by the President who perform executive functions. It has, however, endorsed limits on the removal of principal officers who head independent agencies. See Humphrey’s Executor. It has also endorsed limits on the removal of an inferior officer, see Morrison v. Olson, 487 U.S. 689–90 (1988), but not where that officer’s superiors cannot be removed at-will by the President. See Free Enterprise Fund v. Public Co. Accounting Oversight Board., 561 U.S. 477 (2010). Given the nature of the FBI Director’s duties and his appointment by the President, it seems almost certain that the FBI Director would qualify as a principal executive officer and would be one of the persons subject to the “exclusive and illimitable power of removal” described in Myers. (The Director of the FBI was once appointed by the head of a department, but, as was the case with the Postmaster in Myers, see 272 U.S. at 163, the manner of appointment shifted through legislative action. See 28 U.S. Code 532, note.) See also Free Enterprise, 561 U.S. at 515 (Breyer, J., dissenting) (“The separation-of-powers principle guarantees the President the authority to dismiss certain Executive Branch officials at will.”). With that in mind, it would seem rather odd if Congress could not place restrictions on the removal of the FBI Director but could make his removal a federal crime. See also Nixon v. Fitzgerald, 457 U.S. 731, 750 (1982) (the President must have “an unrestricted power to remove the most important of his subordinates in their most important duties'”) (quoting Myers).
 The Criminal Court in Ex Parte Perry stated that it policed separate of powers more closely than do federal courts, especially in light of the express separation of powers provisions contained in the Texas Constitution. (Separation of powers in the federal constitution is communicated through the separate vesting clauses, rather than through any express provision.) Presumably, the Criminal Court was referring to the Supreme Court’s occasional functionalist approach when it referred to adopting a stricter standard.