A new lawyer took the field last week in the Russia investigations: attorney Ty Cobb, appointed by President Donald Trump as White House special counsel. Cobb’s client is different from those of the expanding list of lawyers working on Trump administration investigations issues; indeed, his client is the presidency itself.

It is his job not to defend Trump personally but to ensure the presidency as an office is not harmed. And there are indeed many ways in which the presidency can be harmed, perhaps with long-lasting consequences.

As a lawyer who has spent much of my career representing public officials and agencies — including three governor’s offices in impeachment proceedings — I am constantly reminded that the offices of the public officials are just as endangered by the investigative proceedings as the officeholders themselves. Cobb’s role will be to try to protect the office of the presidency from impediments that arise during the investigation, and to defend its particular privileges and powers from any incursion along the way. However one feels about Trump himself, every American should be rooting for Cobb to succeed.

How will Cobb help protect the presidency? First, investigations can disrupt the functioning of the presidency and the executive branch of government. They occupy focus, attention, time and personnel that might otherwise be devoted to addressing critical executive functions of government such as national security, defense and the economy. Cobb will streamline the White House response to investigations and appropriately guard against unnecessary distraction from the essential work the American people have elected the president and his administration to do.

Second, investigations can affect the presidency’s constitutionally defined power and authority. The Constitution contemplates an elected president who will serve as the head of the executive branch of government, subject only to limited controls, such as congressional confirmation of certain executive branch personnel. An employee of the executive branch, even a “special counsel” appointed by the deputy attorney general, cannot unduly interfere with the operation of the presidency. So Cobb will help ensure that the work of the president and his administration is not disrupted, even while recognizing that law enforcement investigations are a critically important executive branch function.

Similarly, the Constitution provides for the allocation of powers among the executive, legislative and judicial branches. To be sure, Congress has a well-established oversight role. So those in Cobb’s position during previous administrations — including those of Presidents Barack Obama, Bill Clinton and George H.W. Bush and George W. Bush — have generally worked to facilitate efficient cooperation with congressional inquiries. Nevertheless, they also safeguard against any efforts by Congress to overreach in a way that could disrupt the delicate balance and separation of powers embodied in the Constitution.

How does this play out in the real world? The White House will almost certainly receive demands for information from Special Counsel Robert Mueller. It will be up to Cobb to make sure these demands are evaluated and complied with, assuming they are lawful. This involves working with White House staff members to identify responsive information and, subject to any applicable privileges, producing it promptly. Cobb would also represent the presidency’s interests in connection with any requests for interviews or testimony from White House staff members.

If Cobb thinks Mueller’s demands are unlawful, perhaps because they are too broad or they are for information protected by executive privilege or attorney-client privilege, Cobb must evaluate the demands and advise the president. There are few U.S. Supreme Court decisions to consult for guidance, but Cobb will no doubt review those and any relevant lower court decisions.

These kinds of disputes have come up in the past. The Clinton White House, for example, went to court to argue that documents and testimony demanded by an independent counsel were protected from disclosure by the attorney-client privilege. There was also litigation when Clinton claimed executive privilege related to documents demanded by an independent counsel in connection with an investigation of former Agriculture Secretary Mike Espy. It will be up to Cobb to advocate for the presidency in addressing these kinds of issues should they arise.

Trump’s administration will also continue to get inquiries from Congress. Cobb will have to help the White House comply with these inquiries assuming they comport with constitutional notions of separation and balance of powers. Were Congress to push its constitutional boundaries, Cobb will likely negotiate a resolution, and if not, the matter may go to court: A recent example is when Congress filed a lawsuit to obtain documents from Obama’s attorney general and Justice Department, despite the Obama administration’s claims of executive privilege.

It was crucially important that the president designate a lawyer to represent the presidency in the current investigations. Without someone to fill this role effectively, there could be long-term consequences for the office. For example, the way the Nixon White House responded to the Watergate investigations caused lasting public mistrust of presidents, resulted in Supreme Court precedent eroding the president’s executive privilege and tipped the political balance of powers toward Congress and away from the presidency. To prevent further damage to the presidency — no matter how one feels about Trump in particular — it is paramount that Cobb succeeds.

Ross Garber is a lawyer whose practice has focused on representing public officials and agencies in investigations, including investigations and impeachment proceedings for three U.S. governors.