A just cause!
Sometimes, a just cause is truly important.
Sure, following in the Allies' footsteps and simply taking over as the receiving official would be nice—you could gain everything with almost no cost.
But while it's tempting, it would also plant seeds of trouble for the future—how could Borneo remain untouched amidst the wave of colonial independence?
But what if Borneo was liberated from Japanese occupation by its own people?
The liberator—that's the just cause.
That's the legitimacy for ruling Borneo in the future.
Just like the "Big Five" powers—no matter how the world questions them, one fact remains unchangeable: the Big Five were founded on the anti-fascist victory of WWII. Any country wanting to challenge their legitimacy would first have to destroy the United Nations.
Beyond the just cause, for Pierre, this was also an opportunity!
An opportunity to control—no, to liberate—the whole of Borneo.