I just finished Rubicon by Tom Holland and wow, it really made all the big personalities of the time feel alive and dove into the complexities of how the republic worked.

My understanding is that some of Caesar's rivals wanted to prosecute him for invading Germany and Britain, which was technically illegal, so that they could check his growing power and popularity. However, what I don't get is why Pompey agreed to allow his ally to be prosecuted when he had the power to let Caesar avoid prosecution and make a run for console.

The Triumvirate was obviously broken with the death of Crassus, but did Pompey fear that Caesar would eventually turn on him after gaining a better position as a console, or did Pompey just want to appease the senate? Was there anything else influencing his decision?