Let the parlor game begin. As Americans wake up to the scathing resignation letter from Secretary Jim Mattis, Washington chatter is already moving on to the inevitable question of “who is next”? Who will the President tap to take up residence in the E-Ring and run the world’s largest employer and most effective fighting force? Who will have the responsibility for overseeing the withdrawal from Syria, Afghanistan, and who knows where else? Who will have the privilege of defending the White House’s military policies in front of a congress where both Democrats and fellow Republicans feel more emboldened to question the Commander in Chief.

Not to be flippant, but who cares? Or, more precisely, does it matter?

The slippery slope that started with the whispers that Donald Trump didn’t need a communications director (because he is his own communications director) has turned into a landslide that has swallowed up the office of the Secretary of Defense. When John Kelly’s departure was announced just weeks ago the refrain was the same—why does Trump need a chief of staff — he is his own chief of staff. When the President bucked his foreign policy and defense advisors and enacted a pullout from Syria just days ago via tweet, he signaled that the same was true for SecDef. (And, arguably, for the National Security Advisor.)

Someone will be appointed, and someone will be confirmed, but the President has now proven that he cares more about his twitchy Twitter trigger finger than what experience, insight, and advice a candidate might bring to the Pentagon.So, it may matter less “who is next” than “who comes after that.” Leaving the odds-making on a midterm exit for the President to those much smarter than myself, let’s assume the earliest that we will see a non-Trump SecDef will be January of 2021. What will they be walking into through the River Entrance doors? For the first time since the post-Vietnam era, I argue, they will be walking into a large-scale rebuilding project.

The Trump presidency will leave our armed forces bruised, and its first post-Trump leader will have to make the repair job their number one priority. They will need to start by rebuilding trust. You can’t run the world’s leading military when no one believes what you are saying to them, even if it’s just because no one believes your boss. Trust in military affairs is based on clarity and consistency—saying what you will do, doing it, and making it clear when and why you are changing course. It is the bedrock for the Pentagon’s effectiveness, and after two years of this administration and despite the best efforts of Secretary Mattis and his team it is broken with almost every group of stakeholders that matters.

They will need to rebuild relationships. Allies will need to be brought back into the fold. The bridge to congress that every effective SecDef has nurtured and leaned on will need its own infrastructure project. The unique relationship with the press that lives inside the Building will need to be rebooted. And the American people will need to know more, not less, about what its military is up to so they can feel confidence in its actions.

They will need to rebuild processes. When you are talking about putting America’s sons and daughters into mortal danger you need to have systems and processes in place that ensure the facts you are depending on are correct, that the decisions you are making are sound, and that all the options have been considered. When those systems are ignored or circumvented they begin to crumble. Similar systems exist for interacting with our allies and our advisories so that we are able to avoid unneeded confrontation and maximize the impact of our actions. Those processes will need to be reengaged and reinvigorated.

They will need to rebuild morale. Sudden changes in strategy, ignoring senior military officers, unnecessary holiday season deployments to the border—all of these actions erode morale. The decisions that are made in the Situation Room ripple down to the most junior personnel in the military, and the instability that Trump creates threatens the confidence of everyone in uniform. That is a problem, and it will need to be addressed.

America leads because it is not only good for the world, but it is good for America. Decades of work building systems and relationships that allow us to sit in that leadership position are being thrown out the window, weakening our position not just militarily, but diplomatically and economically. When the world can’t trust what America says, when America isn’t seen as a leader by our allies or our advisories, then we are worse off. The next SecDef will arguably be a caretaker. The SecDef after that will have a yeoman’s job ahead of them, a rebuilding effort with global consequences.