The AI (usually) favours expanding over fighting other players.
The AI does (under certain conditions) complete bonuses by taking over territories from team mates. While there doesn't seem to be a way to force it to do so, the following are some things to keep in mind:
- It will only do so when it has at least half of all the bonuses in a territory (this was stated by Fizzer)
- It will only start taking over territories from team mates when each territory in the bonus is controlled by their team
- Having only a single defender seems to greatly increase the AI's willingness to attack
- The AI does not seem to consider completing bonuses a very high priority; if it can find another use for its armies elsewhere on the map, it will often do so