Ceaser is trying to raise more money and troops to go and fight some more foreign campaigns however is having some trouble with the Senate (don't we all?). Basically they don't want to approve any more wars until Ceaser gets Rome's house in order, which basically means subduing the rebellious village in Northern Gaul that we all know so well. However, as has become clear by now, because they have a magic potion, defeating them by shear force of arms simply will not work, so they need another plan – thus enters Convulvulus, a guy whose presence simply sets people at each other's throats, and a simple word can send people into a frenzy of anger.
The idea is to divide the village so that they are too busy fighting amongst themselves to worry about fighting Rome. The problem is that when left to their own devices they generally fight among themselves anyway, it is just when the Romans decide to pay them a visit, then they will all get together, put aside their differences, to bash the Romans, which obviously makes this task somewhat more difficult.
I am feeling that by part of the series the Asterix books are not really doing anything new. In a way they are not like the Tintin albums, which simply got better and better the more I read them (and I am not sure if I actually read them in order this time, but I know that I now have the complete collection). In a way I find Herge's writing to be a lot more engaging, and substantially funnier, than the Asterix albums, simply because, in the end, they always drink the magic potion, and always end up beating up the Romans.
One interesting thing that I note is the question that is raised in this comic of the fact that Asterix does not have a wife. Then we see Asterix and Obelix fighting, and then running back into each others arms because they can't be angry at each other for too long. It does raise some eyebrows, however I do notice that at least twice Obelix has fallen in love with a woman (or was that only one comic, and I am getting mixed up with one of the movies), though poor Obelix lucks out. I'm not sure why the writers chose not to give Asterix a wife, but maybe it is because they didn't feel that he needed one.
It is also interesting that the Senate refer to this village in Gaul as being rebellious but it is not as if they are actually trying to expand their territory – they are pretty content simply to live their own lives in their own self sufficient village (which does not need money) and let the world drift on behind. I suspect the problem with this though is the fact that they are not paying taxes to Ceaser (and this has been indicated an a previous comic that tax collectors have pretty much learnt not to attempt to collect taxes from this village). However, I suspect that it is because they do stand up to Rome that they are seen as a threat that must be subdued because if they stand up to Rome, then that will only encourage others.