One of the problems with understanding the Ukraine impeachment proceedings is that while there is a one-sentence summary of what Trump did – he hijacked American foreign policy to attempt to extort an investigation of a political rival from a desperate and dependent American ally – there is no good and simple explanation of the sheer gravity of the harm that Trump stood to inflict on American national interests.

And it’s in understanding the gravity of the harm that Americans can begin to answer the question, “Why now?” Even if Trump did do something wrong, why impeach him during an election year? Why seek to remove him the very year when voters can render their own judgment on his candidacy?

The answer is short – because Trump’s corruption could have had profound strategic consequences – but the explanation is a bit longer, and it requires the assistance of a very helpful and timely report on Russian military capabilities from the RAND Corporation.

The report is long (99 pages) and detailed, but the relevant summary is relatively clear. Many Americans are aware of Russia’s capabilities in cyberwarfare and disinformation operations, but they’re largely unaware of advances in its conventional military capabilities. Russia has accomplished two things of real importance in the past decade (or so) of military modernization. First, it has substantially modernized and professionalized its force. And second, it has optimized it for operations that are virtually custom-designed to place NATO, our most vital international alliance, in perhaps an impossible military, strategic, and political bind.

Russia’s military progress has been on public display in two vital world regions – the Middle East (where it has proved remarkably effective at defeating the Syrian regime’s internal enemies) and, crucially, in Ukraine. In the Rand report’s words, when Russian forces invaded Crimea in 2014, “few were surprised by the annexation,” but “many were surprised by the performance of the Russian armed forces. Russian soldiers in Crimea were competent, capable, and professional, three terms that had not been applied to the Russian military in quite some time.”

Indeed, in the much bloodier fighting in southeastern Ukraine, Russian forces have “generated decisive advantages over Ukrainian ground forces,” and they’ve also “made Western militaries pay increasing attention to the threat that the Russian military would pose in any future conflict in Eastern Europe.” The RAND report assesses that “Russian Ground Forces have local dominance along its European and Central Asian borders.”

In many ways, Ukraine is a testing ground for the kind of fight that could ultimately break NATO. Brian Nichiporuk, one of the report’s co-authors, raised the specter of what he called a “smash and grab” operation – where Russia uses the capabilities it has honed in places like Ukraine to launch a rapid invasion of, say, Estonia, immediately incorporate the invaded nation into its formidable defense perimeter, and present the invasion to the world as a virtual “fait accompli.” That is exactly what happened in part of the Ukraine.

Would the United States commit its forces to a brutal, bloody battle to liberate its NATO ally? Or would the likelihood of serious casualties – combined with the extraordinary difficulty of the operation – cause the public to demand that America abandon Estonia to its fate? If so, could the NATO alliance survive intact after Russia demonstrated that the combination of its might and will could make a superpower yield?

These sound like esoteric, theoretical questions – far removed from the daily lives of the American public. But these are exactly the kinds of strategic questions that presidents and their advisers should ponder. And the answers to those questions should drive American policymaking.

During the impeachment hearings, American public servants (diplomats, national security officers) tried their best to describe American national security interests at stake in Ukraine. Here’s one way to phrase those interests – an effective Ukrainian defense against Russian aggression raises the cost of that aggression and (crucially) raises the perceived cost of future aggression.

A Russia that can simply walk over Ukraine is a stronger Russia – a nation that one day may feel emboldened to take even greater risks to secure regional dominance and strain the western alliance. A Russia that is bogged down in a fight against a well-armed foe is less likely to seek another fight – especially a fight with much higher risks.

This fundamental understanding is one reason why many Americans were rightly deeply frustrated with the Obama administration’s refusal to provide Ukraine with lethal military aid. Yes, there were valid concerns about escalation, but the bottom line is that Ukraine needed better and more modern weaponry to – at the very least – deter substantial new Russian offensives.

And so it was at one point deeply encouraging that Congress and the Trump administration at least appeared to be in agreement. Ukraine needed lethal military aid, and Congress appropriated money to fund that aid. Now we know that there was a dissenter – the President of the United States. And he dissented not because he’d made a careful (though contentious) assessment of America’s best strategic interests, but rather because he was nursing various domestic American political grudges against the Bidens and driven by unfounded conspiracy theories.

No one should think there is any magic policy wand that will resolve America’s strategic challenges in Eastern Europe and restrain Russian action to our liking. Every course of action has its perils, but that’s exactly why we need a Commander-in-Chief who is intellectually engaged, strategic in this thinking, and motivated by the American national interest.

Trump, by contrast, is ignorant, impulsive, vulnerable to conspiracy theories, and motivated by his own personal grievances and grudges. Crucially, he indulges these vices even when the stakes are very high. He was not holding up the opening of, say, a Consulate in Costa Rico for corrupt personal reasons. He was holding up the provision of weapons to an ally locked in a critical conflict with one of our primary geopolitical foes – a foe that we now know is growing in military power.

Eight months ago – just as the Mueller investigation was winding down – I argued in these pages that an election, not an impeachment, was the most prudential way to hold President Trump accountable for his misdeeds. The Ukraine scandal changes the calculus. It demonstrates that the president will inject his vices even into the most consequential strategic decisions.

It’s not just the nature of Trump’s abuse of power that argues for his impeachment, it’s the gravity of harm that he risked with his reckless malice.

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