Whatever else he may or may not do to Ukraine, one thing can now be said with certainty about the malign legacy of Vladimir Putin's actions towards Ukraine - there will be those who make a convincing argument that it could be said even before the present crisis.
And that is that he has dealt any hope of nuclear disarmament and the cause of non-proliferation of nuclear weapons a blow from which it may never recover.
On the dissolution of the former Soviet Union, Ukraine was left with about a third of the former Soviet nuclear arsenal - about 1,700 warheads, one of the three largest stockpiles of nuclear weapons in the world. There were also former Soviet nuclear weapons in Belarus, Kasakhstan and, of course, the Russian Federation,
At an OSCE conference in Hungary in December 1994, Ukraine, Belarus and Kasakhstan agreed to surrender or destroy all their nuclear weapons in exchange for security guarantees from all the great powers.
In particular, under the terms of the Budapest Memorandum, Russia, the US and the UK confirmed their recognition of Belarus, Kazakhstan and Ukraine becoming parties to the Treaty on the Non-Proliferation of Nuclear Weapons and effectively abandoning their nuclear arsenal to Russia and that they would:
- Respect Belarusian, Kazakh and Ukrainian independence and sovereignty in the existing borders.
- Refrain from the threat or the use of force against Belarus, Kazakhstan and Ukraine.
- Refrain from using economic pressure on Belarus, Kazakhstan and Ukraine to influence their politics.
- Seek immediate Security Council action to provide assistance to Belarus, Kazakhstan and Ukraine if they "should become a victim of an act of aggression or an object of a threat of aggression in which nuclear weapons are used".
- Refrain from the use of nuclear arms against Belarus, Kazakhstan and Ukraine.
- Consult with one another if questions arise regarding those commitments.
The USA and the Russian Federation jointly reaffirmed those promises and guarantees to Ukraine as recently as 2009.
The theft of the Crimea by Russia in 2014 was a serious breach of the Budapest Memorandum, but Russia's further actions this week and Vladimir Putin's speech amounted to a clear repudiation of the agreement.
The question now has to be asked, in the light of this clear breach of faith by the Russian president, what government in their right mind would give up nuclear weapons in exchange for such a guarantee in future - and the answer to that question, surely, is none.