Dismissals of federal independent agency leaders have been a hallmark of President Trump’s second term. Scores of officials have contested their firings in federal courts, and the Supreme Court will soon judge the constitutionality of their removal. Trump has also targeted officials in legislative branch agencies. Last year, Trump abruptly fired the Librarian of Congress and the director of the Library’s U.S. Office of Copyrights. The Court on a temporary basis has almost uniformly sided with the president and refused to block his removals. But we don’t know yet how the justices would view the president’s authority to summarily dismiss legislative agency leaders.

A broader question looms: In a period of ever-expanding assertion of executive authority, can Congress insulate its legislative agencies from presidential encroachment?

The question is particularly salient today. The comptroller general—the legislative branch’s non-partisan fiscal watchdog—serves a fifteen-year term and heads the Government Accountability Office (GAO). The term of the most recent comptroller general ended this past December, leaving GAO in the hands of an acting official. The comptroller general is no obscure accountant. Lawmakers rely on the comptroller general to protect Congress’s power of the purse by holding the executive branch accountable for how it spends taxpayer dollars. Recognizing the importance of insulating GAO from partisan winds, Congress changed the law in 1980 to guarantee Congressional leaders a role in recommending comptroller general nominees to the president. Will the president abide by the letter and spirit of the law to select one of Congress’s preferred nominees? Or will he instead choose a candidate based on loyalty to President Trump rather than the interests of Congress? We’re about to find out.

First, some history. The roots of government auditing and accounting run deep in American history: Congress in 1789 implanted in the Treasury Department the “Comptroller of the Treasury,” reflecting that lawmakers originally viewed oversight of government expenditures as an executive function. Congress periodically revamped the form and function of the office but always kept it under the Treasury’s eye. As government spending and debt rose in the wake of World War I, however, Congress overhauled government finances by enacting the 1921 Budget and Accounting Act (BAA). As political scientist John Dearborn argues, the BAA institutionalized a central role for the president in the exercise of the legislative branch’s power of the purse: It mandated that the president spearhead the formulation of a novel unified federal budget.

The price of enactment for sharing budgetary powers with the president? Congress took the audit function away from the executive branch and gave it to a newly created independent agency reporting directly to Congress. Although the president would appoint and the Senate confirm the new comptroller general, Congress initially retained sole removal authority. President Wilson vetoed that version of the bill in 1920. As enacted the next year, the BAA forced Congress and the president to share “for cause” removal authority. If the president vetoed a joint resolution agreed to by Congress to remove the comptroller, both chambers would have to override the veto to remove him.

Fast forward to today. How insulated is GAO from a president’s policy or political ambitions? At first blush, GAO enjoys some autonomy from the executive branch. GAO is a legislative agency: To create GAO, Congress purposively took a rib (government audits) from Treasury and grafted it onto Congress’s body, its new boss. Similarly, the U.S. Government Manual places GAO within the legislative branch. A majority of the Supreme Court in Bowsher v. Synar (1986) thought so too: The Court struck down a provision of a deficit cutting law that directed GAO to identify mandatory spending cuts to be implemented by the administration. Because Congress holds the authority to fire the comptroller, the Court reasoned, GAO was a subservient legislative agency. Giving GAO executive authority to direct the administration to sequester federal spending would breach the separation of powers.

But lines between the branches are not always easily drawn. Legal scholar Anne Joseph O’Connell calls these “boundary” institutions: They live at the border of different authorities. GAO straddles both legislative-executive and legislative-judicial borders. The president appoints the comptroller, pulling GAO into the president’s orbit. But GAO also exercises legislative powers. It responds to requests from lawmakers for information and investigations, and Congress empowers GAO to bring suits if it finds the president has illegally impounded federal funds. At the judicial border, GAO adjudicates roughly a thousand disputes each year pertaining to the awarding of federal contracts. GAO’s porous boundaries arguably create an opening for a president to hire or fire the comptroller general at will on the grounds that GAO is just another independent agency tasked with executive responsibilities.  

To assert its position as GAO’s boss, Congress in 1980 bolstered the authority of GAO in conducting investigations and overhauled the appointment process for nominating a new comptroller general. Congress established a commission of chamber, party, and oversight committee leaders to recommend to the president at least three candidates for the position. The statute allows the president to request additional names but does not require the president to select a nominee from the list.

Three comptrollers general have been appointed under the new law. At first, the process worked smoothly: President Reagan selected the first nominee under the new law in 1981, nominating Charles Bowsher from eight candidates recommended by the commission. Selection of his successor, David Walker, was more contentious. The process dragged on for two years: President Clinton rejected both Congress’s list of three nominees and an additional four candidates forwarded by Democratic commissioners. Clinton asked for more names from the commission, eventually settling on their recommendation of Walker. In 2010, the commission broke down: Republicans charged that Democrats broke off bipartisan talks. Each party sent its own list, but both lists included Gene Dodaro, whom Obama nominated for and the Senate confirmed to the position.

Despite the precariousness of the process, lawmakers and the president have ultimately concurred on the new GAO director. Such agreement may be short-lived. Ever-rising partisanship in Congress—as well as Trump’s limitless view of his Article II authority—could be the death knell for the commission and bipartisan approval of the president’s pick. Lawmakers’ bipartisan, supermajority support would be needed for Congress to president-proof the selection process—not merely for the GAO but for the nine other key legislative branch agencies. (That said, the Senate in 2013 abolished most nomination filibusters, limiting the need for bipartisanship when the president’s party controls the Senate.)

Congress does assign different appointment and removal rules for the leadership of the ten core legislative branch agencies—ranging from the head of the Congressional Budget Office to the chief of the Capitol Police. Taking advantage of the Supreme Court’s opinion that the GAO is a legislative agency might provide one path for authorizing Congress to appoint the comptroller general without presidential nomination. That would align GAO with the bipartisan, bicameral process by which Congress appoints the head of the Congressional Budget Office. Overcoming presidential opposition to such a statutory change, however, would be a formidable challenge.

Ambiguity is a fact of life under the U.S. Constitution: Separate institutions inevitably share power. Such ambiguity also invites presidential aggrandizement of executive authority, especially so today. Time is running out for Congress to muster political and institutional will to protect its non-partisan watchdog—and other ostensibly legislative agencies—from this presidential vortex of power.