The opening statements at Wednesday’s House Judiciary impeachment hearing were full of detailed historical and constitutional analysis on whether President Donald Trump’s Ukraine scandal contains impeachable behavior.

But the most clarifying element wasn’t one of the many quotes from the Founding Fathers, but a simple analogy offered by Stanford law professor Pamela Karlan.

Karlan, called to testify by House Democrats, started by discussing Trump’s infamous phone call with Ukrainian President Volodymyr Zelensky, where he asked the Ukrainian president for the “favor” of investigating the Bidens and 2016 immediately after a discussion of military aid. She then asked the committee to think about how this would look if Trump were on the phone with a governor rather than a foreign state, an exercise that really helps illuminate why Trump’s behavior is so troubling:

Imagine living in a part of Louisiana or Texas that’s prone to devastating hurricanes and flooding. What would you think if you lived there and your governor asked for a meeting with the president to discuss getting disaster aid that Congress has provided for? What would you think if that president said, “I would like you to do us a favor? I’ll meet with you, and send the disaster relief, once you brand my opponent a criminal.”

Wouldn’t you know in your gut that such a president has abused his office? That he’d betrayed the national interest, and that he was trying to corrupt the electoral process? I believe the evidentiary record shows wrongful acts on those scale here.

Here’s a video:

Now there’s an important difference in this analogy: Trump isn’t in charge of Ukraine the way he is Texas or Louisiana. But the US political and military relationship with Ukraine gives him an important source of leverage that makes the analogy work.

Ukraine really is facing a situation akin to a hurricane: a nearly six-year conflict with Russia that has already resulted in Moscow annexing part of its internationally recognized territory. The Ukrainians are fighting for their nation’s survival and see US military aid as a vital form of assistance. That makes the assistance an extraordinary form of leverage — in some ways more vital than a disaster aid, because it can actually help stop disaster rather than cleaning up in its wake. This is how much pressure Trump was putting on Ukraine.

It’s also clear that when Trump asked for an “investigation,” he didn’t actually want a rigorous look at the facts. Gordon Sondland, Trump’s ambassador to the EU who personally worked on obtaining the quid pro quo, testified in November that Zelensky “didn’t actually have to do them [the investigations].”

All Trump wanted was an announcement that of an investigations would happen, which he could use to suggest Joe Biden was linked to criminal or shady behavior in the 2020 campaign — re-running the “Crooked Hillary’s emails” playbook in a new election. It’s exactly like the set-up Karlan described: She later singled out this testimony from Sondland as the “most chilling” moment in his entire testimony.

The hypothetical request to a governor that Karlan described is so obviously impeachable that no one could imagine defending it. Trump’s Ukraine behavior is only slightly different, yet Republicans are (so far) nearly united in his defense.