Yeah, just nationalism and nothing else.

Some Princip quotes:

I am the son of peasants and I know what is happening in the villages. That is why I wanted to take revenge, and I regret nothing.

The oppressed have the right to rise against their oppressors.

Our struggle is not against individuals, but against the system that perpetuates their power.

We are the voice of the voiceless, the hope of the oppressed.

But those are just things he personally said, not a Wikipedia entry, so…