It’s okay to criticize your country/state, that’s how concepts such as democracy began, but people should have some loyalty to their native nations, especially in periods of war. Few things in periods of crisis are as gut-wrenching and terrible as having a traitor abandon the cause and help the enemy.
In this list, we have some of the worst cases of people betraying their fellow countrymen, sometimes knowing that their decision caused thousands of their former comrades to die. It’s important to note that history and those who write it decide who is a traitor, as a quote from author Nihad Sirees explains “You can call anyone you want a traitor as long as you’re the one holding the pen.”
Where most of the Christian world uses Judas as a synonym for traitor, many Greeks still use Ephialties to call out traitors. People are quite familiar with the Battle of Thermopylae with Leonidas and the 300 Spartans (and 7,000 Greek allies). The few Greeks stood against the might of the Royal Persian army, as many as 200,000 men.
In the narrow pass of Thermopylae, the Greek hoplite formation easily chewed through waves of Persians who had no way to flank the wall of shifting armor, shields, and spears in front of them. The lightly armored Persians (even the famed immortals had less armor than the Greeks) had no answer. After two days, the Greeks had lost a few hundred men compared to perhaps 15,000 Persian losses. Some sources even say the Greeks were brave enough to launch a night raid on the Persian camp.
Then Ephialties stepped onto the scene. A Greek native to the area, his home, and nearby city were likely to be sacked if the Persians won, but the Persians were immensely wealthy, and no one was paying Ephialties to stay loyal, so he went to the Persians and told them about a goat path around the Greek position.
The next day the Greeks were surrounded, with a several thousand being able to get away and Leonidas and about 1,000 Greeks stayed to fight to the death. The final day of battle was a slaughter, but the Greeks gave as good as they got until the end, killing five or more Persians for every Greek slain on the last day. They did this despite having most of their spears and swords broke or lost, ripping and grabbing weapons from the Persians.
Had the goat path been left undiscovered, the Persians still likely would have won, but the Greek defense could have lasted several more days at least. Xerxes could have lost upwards of 50,000 men while the Greeks could have had a more orderly retreat. This alternate history could have even made Xerxes give up on his invasion with such heavy losses so early, but Ephialties erased that history. Despite his treachery, the stand did inspire unity and a fighting spirit into the rest of Greece that allowed them to eventually defeat the Persians.