If President Trump hates Bob Mueller so much, why doesn’t he have him fired?

For most Republicans, the concern over firing Mueller is that it would incite a backlash in the 2018 midterm elections, costing them unified control of Congress and imperiling their policy objectives.

But for the president, the concerns are much more personal. A Democratic takeover would be catastrophic. Instantly, the House would be converted into a hive of investigatory bodies. In a Democratic House, the grand Washington battle will no longer be Trump versus Mueller. It will be Trump versus 21 subpoena-wielding House committee chairmen, played out in public on a 24-hour televised loop.

Unlike a legislative agenda, executive oversight can be prosecuted by just one chamber. Taking control of the House would empower Democratic committee chairmen to aggressively pursue every aspect of the president’s personal and political interests. I know a little bit about how this would look. I served as the Democratic staff director of a House oversight subcommittee during the administration of Republican President George H.W. Bush, when Democrats like John Dingell, Henry Waxman, and my old boss, Barbara Boxer, wielded their oversight authority aggressively enough to make agency heads quake. Subpoenas were frequently threatened but seldom required, as Bush administration officials usually came around to the notion that compliance was the better part of valor.

There are 21 House committees that endow their chairmen with subpoena power. Some require a committee vote and/or consultation with the ranking minority member, but none endow the minority with veto power. The expansive subpoena power of Congress is limited only by countervailing constitutional rights. For example, Congress cannot force a witness to waive her right not to incriminate herself. Otherwise, Congress can compel testimony, and the production of documents, from any government employee or private citizen in America.

A House committee can initiate inquiries into any area within its jurisdiction. This investigative authority, and the subpoena power through which it is advanced, has mostly lain dormant in the 115th Congress. When Republicans have exercised their subpoena power, it has mostly been in the service of defending the president against Mueller’s investigation. But that could change in the blink of an eye, as Trump has surely been advised by some old Washington hand.

When it comes to opportunities for congressional oversight, the Trump administration provides what military strategists call a target-rich environment. Every committee that oversees a Cabinet department would have scandals to illuminate and policy messes to untangle. From that viewpoint, here’s what that might look like.

The Ways and Means Committee could sharpen the national discussion around tax fairness by subpoenaing President Trump’s tax returns. As the 2018 elections draw near, that committee could convene hearings to educate the public on how Trump’s sabotage of Obamacare will send consumers’ health insurance premiums soaring.

The Financial Services Committee, chaired by Rep. Maxine Waters, a favorite target of Trump’s invective, could exercise its authority to investigate the phenomenon of foreign oligarchs laundering ill-gotten gains through purchases of luxury condominiums in hot markets, including through Trump-owned buildings in New York and Miami.

The Judiciary Committee might parcel out the most compelling topics to its subcommittees. Subcommittee chairs could empanel Parkland students to attest to the impact of gun violence on schools and administrators to advise on the idiocy of arming teachers, explore the cruelty and shortsightedness of withdrawing DACA protections, and of course, explicate the authority of a special counsel to indict a sitting president.

The Armed Services Committee could convene proceedings on the dangers of sharing state secrets with White House employees who have been denied security clearances.

The Oversight and Government Reform Committee could shine a light on the administration’s profligate spending of taxpayer dollars at Trump-owned properties.

A reawakened House Foreign Relations Committee could initiate hearings on Trump’s erratic courtship of North Korea and his excessive affection for Russia.

The Education and Workforce Committee could call Midwestern factory owners and assembly-line workers to testify on the jobs that will be lost due to Trump’s steel tariffs.

Committees with jurisdiction over the Interior Department, EPA, and Treasury could hold hearings on their leaders’ extravagant travel and personal office expenditures.

Cabinet secretaries like Betsy DeVos and Ben Carson could be compelled to account—in public, under oath—for policy decisions they seem barely to understand.

The new secretary of Homeland Security could be forced to justify her department’s leisurely response to Russia’s ongoing efforts to sabotage American elections.

Now imagine a pajama-clad President Trump gazing in horror at the trio of TV monitors in the presidential bedroom, one showing Jared Kushner being grilled on his never-ending security-clearance-application corrections and amendments, while the second displays Treasury Secretary Steve Mnuchin attempting to defend his addiction to first-class flights, and the third presents a tableau of heartland factory workers displaced by the Bush steel tariffs of 2002. Consider the president’s unbridled anger as he watches a cable-news version of This Is Your Life, a procession of Cabinet secretaries, disgraced former White House officials, unpaid construction contractors, disqualified eligible voters, terrified Dreamers, abandoned factory workers, and colorful NDA signatories, all led by Democratic House committee chairs, many of whom Trump has traduced in nasty personal terms.

With that image in mind, you can see why Trump stops short of firing Mueller. If a rash decision to dispatch the special counsel costs Republicans their House majority, the president will subject himself to a ceaseless barrage of charges, confessions, and revelations. For Trump, that’s the nightmare scenario.