[Goose]

Assuming Putin is purely Machiavellian and doesn't care about the suffering of the Russian or Ukrainian people, is there a decision calculus that would say, in retrospect and with hindsight, Putin did the right thing by attacking?

Hard to justify on any benefit/cost analysis. Putin has lost his oil and gas business in Europe. Improbable he gets it all back, and what he does get back will now be competitive. He will need to offer deep discounts. That alone probably makes the war a net loss. He will be ruling a destroyed Ukraine that will need massive investment to get it back even to where it was before the war. Russia can't afford to do so, especially after this war. Ukraine had a minuscule GDP before it was wrecked. It was much poorer than even Russia. Add to this the sanctions and the impounded funds Russia will never get back. Economically, now and going forward, it is a disaster for Russia.

Politically, it is harder to analyze. Putin wants to re-create the Russian empire, at least in the main. To do that, he needs Ukraine. Back in 2014 Russia still had a shot at converting Ukraine to a vassal state, like Belarus. After Russia seized Crimea, that became very improbable. Given that, invading Ukraine became almost a necessity to meet Putin's goals. So, it became a question of timing. It was obvious that Putin expected a 3 day war. He didn't get that. Had he chosen to strengthen and modernize his military before he attacked, he could have had his 3 day war. He perhaps could have had it if he had just "trained up" the forces he had. He didn't do that either. We can say for sure Putin's timing was definitely "bad". 

In the end, Putin may get absolute control of Ukraine. That was his goal. However, the "side effects" may destabilize his rule. If that happens, his attempt to re-create the Russian empire will have failed. We don't know yet. Therefore, we can't say yet if he achieved his political goal.

[Goose]

Assuming Putin is purely Machiavellian and doesn't care about the suffering of the Russian or Ukrainian people, is there a decision calculus that would say, in retrospect and with hindsight, Putin did the right thing by attacking?

Hard to justify on any benefit/cost analysis. Putin has lost his oil and gas business in Europe. Improbable he gets it all back, and what he does get back will now be competitive. He will need to offer deep discounts. That alone probably makes the war a net loss. He will be ruling a destroyed Ukraine that will need massive investment to get it back even to where it was before the war. Russia can't afford to do so, especially after this war. Ukraine had a minuscule GDP before it was wrecked. It was much poorer than even Russia. Add to this the sanctions and the impounded funds Russia will never get back. Economically, now and going forward, it is a disaster for Russia.

Politically, it is harder to analyze. Putin wants to re-create the Russian empire, at least in the main. To do that, he needs Ukraine. Back in 2014 Russia still had a shot at converting Ukraine to a vassal state, like Belarus. After Russia seized Crimea, that became very improbable. Given that, invading Ukraine became almost a necessity to meet Putin's goals. So, it became a question of timing. It was obvious that Putin expected a 3 day war. He didn't get that. Had he chosen to strengthen and modernize his military before he attacked, he could have had his 3 day war. He perhaps could have had it if he had just "trained up" the forces he had. He didn't do that either. We can say for sure Putin's timing was definitely "bad". 

In the end, Putin may get absolute control of Ukraine. That was his goal. However, the "side effects" may destabilize his rule. If that happens, his attempt to re-create the Russian empire will have failed. We don't know yet. Therefore, we can't say yet if he achieved his political goal.