In the first Civ game, all of the world leaders had a hidden aggressiveness rating between 1 and 10 – with Gandhi's being 1, meaning that he was super docile throughout most of the game. But when someone unlocked "Democracy" on the advancement tree, there was a worldwide 2-point reduction in aggression. But since Gandhi was only at 1, subtracting 2 caused the rating to roll back to 256 – which is the highest value you can encode on an 8-bit system.

So now he has an aggressiveness rating of 256 on a 10-point scale. So I'm sure you can imagine what starts to happen once India acquired nukes.

In Civilization 1, Gandhi had a very low aggression meter/counter, but at some point, the meter clocks back at the highest value, thus giving way to warmonger Gandhi