If someone is so pig-headed that he won't budge on an issue, call him recalcitrant. Not that it will make a difference...
Recalcitrant is from Latin calcitrare, meaning "to kick," so someone who is recalcitrant is kicking back against what's wanted of them. Synonyms are unruly, intractable, and refractory, all referring to what is difficult to manage or control. Writers are frequently referring to recalcitrant Democrats and Republicans, since many people are stubbornly loyal to their political parties and unwilling to change.
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