Amidst the distractions of the coronavirus crisis, the efforts to federalize policing of cities, and the recent results of his cognitive test, it should be not surprising that President Trump took the opportunity to commute the prison sentence of Roger Stone. The decision to do so, presumably, was meant to reward the loyalty of his friend and guarantee that Stone would not disclose any potentially damaging information about him.

This use of the pardon power is problematic under the Constitution. The framers saw elections as the means by which the American people could hold presidents accountable for the exercise of the pardon power. But the framers did not reckon on the 22nd Amendment, which limits a president to two terms, and they likely did not reckon on a president with as much potential to abuse his executive branch authority as Trump.

The pardon power is understood to have few justiciable limits. A president cannot pardon, for instance, the commission of state crimes. But that has not stopped Judge Amy Berman Jackson, who presided over the case of Stone, from seeking to inquire whether the commutation includes both the prison term and the supervised release. The Justice Department has insisted the commutation extends to both forms of punishment.

In pursuing this inquiry on the terms of the commutation, Jackson has the opportunity to at least educate the public on another limit on the pardon power, which is its unavailability, according to the text of the Constitution for cases of impeachment. As Corey Brettschneider and Jeffrey Tulis have explained, the exception for cases of impeachment suggests a president cannot use the pardon power to help those “people directly associated with any impeachment charges” against the president himself.

This view makes sense. The framers sought to ensure that federal actors would be accountable for any authority that they might exercise under the Constitution. As Brettschneider and Tulis maintain, presidents can only be accountable “if they are precluded from thwarting legislative and judicial inquiries into their own potential abuse of power or of their failure to take care that the laws and duties of the office be faithfully executed.”

In the case of Stone, this argument finds support in basic separation of powers principles. The Supreme Court held this term in Seila Law versus Consumer Financial Protection Bureau that, simply because Congress has the authority to determine the structure of the executive branch, does not mean it can limit the ability of the president to remove executive branch officials. This restriction would undermine the executive authority of the president as granted under Article Two of the Constitution.

This reasoning applies to White House efforts to undercut Congress. As the Supreme Court has noted in Donald Trump versus Mazars Company, the “power of inquiry, with the process to enforce it, is an essential and appropriate auxiliary to the legislative function” of Congress. Lawmakers can therefore request documents and testimony from executive branch officials when such evidence relates to a legitimate inquiry.

This power would mean nothing if the president could instruct those who work for him to lie to Congress, knowing they could be pardoned for their crimes. To paraphrase Supreme Court Chief Justice Roberts, writing in the Mazars Company case and quoting Alexander Hamilton, without limits on the pardon power, the president could “exert an imperious control” over Congress and raise itself at the expense of the legislative branch.

Stone was convicted for lying to the House Intelligence Committee. A commutation of his sentence thus diminishes the power of Congress to engage in oversight of the executive branch. Compare his commutation to a hypothetical pardon of Michael Flynn, who admitted to making false statements to federal officials. This specific pardon would not transgress the separation of powers because it would not undermine Congress. This would instead betray the federal law enforcement agents and attorneys of the executive branch who had investigated and prosecuted Flynn.

While the abuse of the pardon power in the case of Stone may be a matter of the Constitution, judges are limited in the ability to review the exercise of this authority. Jackson could, using her inquiry into the commutation, shed light on an act that appears to serve not justice but the political and personal fortunes of the president and his loyal but criminal friend.

Lawrence Friedman is a professor at New England Law in Boston, where he teaches constitutional law. He is the author of “Modern Constitutional Law.”