Just Say Perhaps: When powerful characters smash your setting

I have made frequent comment in interviews on the need for the Gamemaster to adapt to PC power levels in Sertorius. This means being open to the possibility of drastic change in the setting at the hands of the players. For some GMs this is a terrifying proposition, it can shatter their carefully laid plans and lead to all kinds of chaos (not to mention the deaths of beloved NPCs). But this also creates potential for more adventure and excitement and gives the players greater stake in the game world. 
There is a common bit of advice that goes "Just say yes". That has never quite worked for me, because sometimes the answer ought to be "no". However "Just say perhaps" captures the spirit of my point about powerful characters. 

There are two things I don't really like as a player. One is when the GM clamps down on clever plans or legitimate actions taken by the PCs, because he doesn't want the adventure or the setting disrupted. The other is when he hands them victory even though their plans ought to have failed for obvious reasons. The impulse to protect your setting is understandable. The impulse to keep an adventure on track is also understandable. The impulse to protect and make this easy for the players is also understandable. But managing both becomes much easier when you allow the players to contribute through the actions of their characters. Protecting players takes away much needed risk int he game. In such cases it is also crucial to say "perhaps" and let the dice fall where they may.

In my second post on our Orcs of the North campaign, Bill did exactly what I am describing (here: ORCS OF THE NORTH). In that adventure we plotted the assassination of General Brogustu of Caelum. This wasn't just any character. This is a big name NPC in the book, whose presence adds a lot of flavor to the Caelum Republic. He is a bit like Caesar and Augustus rolled into one, marching the republic toward Civil War and establishing himself at the  center of a cult of personality. He is my favorite character in the game and one of Bill's as well. But Bill was willing to allow us a chance to take him out. 

Bill said "perhaps". He didn't say "yes". He didn't say "no". We said we wanted to kill the General and he allowed us to try. 

It should be pointed out, we almost didn't succeed. There were many moments where the dice nearly turned against us. This is not only what made it exciting, but made our final impact on the setting that much more meaningful. We could just as easily been caught and executed. Perhaps one or two of us would have escaped; even so, the possible consequences for a failed plot against the general were visibly severe. 

In the end, we succeeded. Brogustu died and now Bill has to deal with the setting fallout that creates (and since Bill is running the campaign I have no idea what direction he will go with that). Our characters do get to return to Atroxis as heroes but Caelum is also sure to respond (and the internal political dynamics of Caelum are likely to shift considerably). 

Clearly this is a golden opportunity for Bill to weave all kinds of interesting adventure hooks. Our positions in Atroxis will change (leading to potential campaign developments), bounty hunters may come after us, and a war between Caelum and Atroxis went from being almost an impossibility to likely indeed. And all this because Bill said "Perhaps".