The Dharmakshatri of Dhrutarastra

Dhrutarastra starts with dialogue in Bhagavad-gidha. Wherever I can practice my dharma is my dharmakshatri, he says. Duryodhana was addressed as Raja by Sanjaya because he was the effective king. So even though both were the descendants of Kuru, they don't call the Pandavasans as Kauravas, only Dritresana, Kaurvas.