Washington • I want to hear the Democratic presidential candidates explain, convincingly, how they’re going to beat Donald Trump. Then I want to hear how they propose to repair the devastating damage Trump has done to all three branches of government — and to our trust in our institutions.

First, Trump has to be sent packing. I shudder to think of what four more years of this chaos and decay would do to the nation. Trump is so unpopular, and has so neglected making any attempt to broaden his base, that the agenda of the eventual Democratic nominee is clear: motivate loyal Democratic constituencies to turn out in large numbers; win back at least some of the Rust Belt voters who chose Barack Obama in 2008 and Trump in 2016; and invite independents and anti-Trump Republicans along for the ride.

None of these tasks are mutually exclusive, and none involve rocket science. With just a couple of exceptions, I can see any of the Democrats on stage last Thursday getting the job done. But then would come the hard part.

Perhaps the most straightforward and least complicated undertaking, since it would be entirely within the next president's purview, is rebuilding the executive branch from the corrupted ruin Trump will leave behind.

One of the most underreported stories about the Trump administration is its basic incompetence. Perhaps Trump's biggest con of all was convincing his supporters that he was some sort of business wizard with a genius for management. In truth, the Trump Organization was a mom-and-pop family business that he repeatedly micromanaged to the brink of collapse. He is doing exactly the same with the government of the United States.

The White House itself is less like “The West Wing” than like “Game of Thrones.” Courtiers vie for the favor of the Mad King, unable or unwilling to perform normal duties for fear of risking Trump’s ire. Usually, the White House is a place where information from outside sources is synthesized and digested so the president can make the best possible decisions. Under Trump, the flow is reversed — his whims, however ill-informed or contradictory or just plain loopy, are tweeted out and must be made into policy.

Agencies vital to our national security — including the Department of Homeland Security and the Federal Emergency Management Agency — lumber along, month after month, without permanent leadership. "It's easier to make moves when they're acting," Trump has said, but really the situation reflects his own insecurity. By keeping his underlings weak and beholden only to him, he limits their power — and thus hamstrings the departments they nominally lead.

So the first job of the next president will be to restock the executive branch with the kind of competent, dedicated professionals who have served both Democratic and Republican administrations in the past. This will be a big endeavor, but it's relatively straightforward.

More difficult is figuring out how to address the damage Trump has done to the legislative branch. With the help of Senate Majority Leader Mitch McConnell, R-Ky., Trump has rendered Congress all but impotent. Even measures with upward of 90% public support, such as universal background checks for gun purchases, cannot even get an up-or-down vote because Senate Republicans are so terrified of Trump's displeasure.

Even if voters hand control of the Senate to Democrats, McConnell will still be able to use the Senate's rules to delay, deflect and disrupt. In that eventuality, would the next president push Senate leaders to get rid of the filibuster? And if the Republicans retain Senate control, which is a very real possibility, do the Democratic candidates have ideas for going over, under, around or through McConnell to make Congress a functioning legislature once again?

Hardest of all will be fixing what Trump has done to the judicial branch. Trump and McConnell have confirmed more than 150 new federal judges, most of them far-right ideologues. Their impact on jurisprudence in the coming decades will be bad; their impact on public perception of the judiciary is already worse.

We need to be able to believe that justice is blind, that our judges are fair and impartial — including those who serve on the ultimate tribunal, the Supreme Court. Trump's brazen court-packing threatens to shatter that belief, and I don't know if anything but probity and time can restore that faith.

Benjamin Franklin famously said that the Constitutional Convention produced "a republic, if you can keep it." Trump will leave behind a banana republic, and his successor is going to have to fix it.

Eugene Robinson

Eugene Robinson’s email address is eugenerobinson@washpost.com.