Underscoring the ongoing geopolitical crisis in eastern Europe, Vladimir Putin's meddling in Ukraine under the pretext of protecting Russian speakers and nationalist rhetoric has important people invoking Hitler's machinations before World War II.

Here are 11 prominent instances where Putin has been compared to Hitler recently:

• Prince Charles to a woman whose ancestors were murdered in the Holocaust: “And now Putin is doing just about the same as Hitler.”

• Former Secretary of State and 2016 presidential contender Hillary Clinton: “Now if this sounds familiar, it’s what Hitler did back in the 30s. ... Hitler kept saying [German citizens abroad were] not being treated right. I must go and protect my people and that’s what’s gotten everybody so nervous.”

• German Finance Minister Wolfgang Schaeuble: "We know all about that from history. Those are the methods that Hitler used to take over the Sudetenland."

• Former Georgian President Mikheil Saakashvili: "In the 1930s, Nazi Germany occupied part of neighboring Czechoslovakia under the pretext of protecting ethnic Germans. Today, Russia is claiming to protect ethnic Russians… in Crimea or Georgian territories… Many in the West are talking about the need to reach some kind of compromise with Russia, an option that smacks of Munich 80 years ago."

• Vladislav Inozemtsev of The Moscow Times: "Like Hitler before him, Putin has no new ideas on how to create a stable global system in place of the current one. He only wants to secure new territory as Hitler tried to guarantee a vast Lebensraum for the German people."

• Former national security adviser Zbigniew Brzezisnki called Putin "a partially comical imitation of (former Italian Prime Minister Benito) Mussolini and a more menacing reminder of Hitler."

• Senator John McCain (R-Ariz.): ""If Putin is allowed to go into a sovereign nation on behalf of Russian-speaking people, this is the same thing that Hitler did prior to World War II. "

• Sen. Marco Rubio (R-Fla.): "Claims that [Russia] needed to move into a neighboring country to protect an ethnic group tied to them is certainly similar to the argument that Hitler made in the 1930s.”

• Sen. Lindsey Graham (R-S.C.): "If you could go back in time, would you have allowed Adolf Hitler to host the Olympics in Germany? To have the propaganda coup of inviting the world into Nazi Germany and putting on a false front?"

• Canadian Prime Minister Stephen Harper: "We haven't seen this kind of behavior since the Second World War."

• Russian activist and former chess champion Garry Kasparov: "Intentionally or not, the Putin regime has followed the Berlin 1936 playbook quite closely for Sochi."

• Washington Post Editorial Writer Charles Lane: "Superficially plausible though the Hitler-Putin comparison may be, just how precisely does it fit? In some respects, alarmingly so."