On comparisons – Yossi Melman in Haaretz:

‘Vladimir Putin is not Adolf Hitler. Even the worst and cruelest dictators of the post war era cannot be compared to the Nazi dictator. Yet some of the measures taken by the Russian president, in his decision to invade Ukraine, are reminiscent of the tactics employed by the Nazi leader prior to September 1, 1939.
It’s called “salami slicing.” Using a toolbox of threats, coercive diplomacy, military force and occasionally seduction, Putin, like Hitler, wants to change the European status quo.’

(…)

‘Putin has a special talent for spotting the weaknesses of world leaders. In 2008 his army invaded Georgia and conquered the breakaway regions of Abkhazia and South Ossetia. Putin gambled that his aggression would be tolerated, and he was right. U.S. President George W. Bush, who was preoccupied with his wars in Iraq and Afghanistan, together with the rest of the West, let it go.
Six years later, Putin sensed the softness of a different U.S. administration – this time of President Barack Obama. The Russian leader invaded Ukraine for the first time, conquering the Crimean Peninsula, and the separatist region of Donbas (Donetsk and Luhansk).’

(…)

‘Obama and his vice president Joe Biden, as well as the EU, did impose sanctions on Moscow after 2014, but they were mild and had practically no effect on Russia’s economy. In their weak, almost submissive response, the U.S. and the West sowed the seeds of Putin’s blatant aggression today.’

(…)

‘Kyiv is not Munich. But by means of appeasing diplomacy in the Chamberlain style, Biden and the Western leaders will only strengthen Putin’s lust for territorial gains. Russian ethnic minorities are also in the Baltic states, which Putin would like to use as a launching pad for his further conquests. Appeasing dictators is not the solution to a problem. It is the problem.
There are indeed signs that at last Biden, British Prime Minister Boris Johnson, French President Emmanuel Macron and even the reluctant German Chancellor Olaf Scholz understand this.’

Read the article here.

No Putin is not Hitler and this is not Munich 1938, for many reasons.

You can have a serious enemy without comparing him to Hitler.

It’s easy to say that the West should have imposed more serious sanctions on Russia after 2015, but the appetite in the US and the EU to do so was rather small, to say it politely.
Whether more severe sanctions would have convinced Putin to change his course is doubtful.

After Afghanistan and Iraq, the US was not convinced that military intervention was a serious option. Public support for a risky military operation in Syria was rather low. In hindsight Obama could have reacted more forcefully back then to send a stronger message to Putin and his friend Assad. But in 2014 or 2015 it was completely reasonable to stay out of the fight.
Also, because it was not clear who was the real enemy, Assad himself or ISIS.

Appeasing dictators might not be a solution, although name one state who hasn’t appeased one or more dictators, but war is not always a solution either.
To blame the US and the EU for Putin’s aggression is not a serious analysis, and above all, diplomacy can always be labeled weak. That’s why it’s called diplomacy, it’s not always effective, it’s ambiguous, and sometimes it fails, just like let’s say democracy.