Why didn’t Robb (Spoilers: Published)

Ever think to see if he could bring the Dornish on side?

They had similar grievances: The Lannisters being directly responsible for the deaths of ones they loved (Ned, Elia and her children); both are very culturally separate from the rest of Westeros.

If North and South ally, you could pincer Tywin by attacking him from North and South. Or, have one force take KL, in the West, and the other trouble Tywin’s forces in the Easter