Can't really blame them. Even a victory with all three against the United Republic would be Pyrrhic victory. I mean...even if other nations wanted to help them, Britain's navy could stop them from reaching Brazil. Only ones I could really see caring would be the USA and Portugal, but I have non-aggression pact with the USA and Portugal is my ally. Hmm...wonder if they would like their former colony back?

Of course this is all hypothetical. Who knows will happen in the next turn.