If he fires him, the fire-breathing Democrat special prosecutor comes after the midterms...  No whinging about conflict of interest and no legal recourse when that happens. 

He'd be smarter to let it ride with Mueller. Better trying to ride a tiger than a dragon. Having said that, I don't think Trump can either control himself or think two steps ahead. He's going to take himself down, making unforced errors a first year pol sci student would know to avoid.