I’ve read this saying twice in the last few days – “a toro pasado”. It means “in hindsight” and in both contexts it was used in response to people criticising the new PSOE presidential candidate, accusing him of promising to do things that he could have done already. In his defence, it was said that it is easy to make these comments “a toro pasado” – in hindsight – once the bull has gone past.
I would have thought there is one significant but rather important difference between “hindsight” and a bull that has passed. In my limited knowledge of bullfighting, the bull is inclined to turn round and have another go at you from another angle. Rubalcaba’s got quite of lot of that coming his way over the coming months.