INTRACTABLE

not easily managed or directed

stubborn

obstinate
"Intractable metal."

"He had admired his intractable stance on the issues of fiscal responsiblity."

"This intractable attitude was seen as one of President Bush's strong point amongst the stubborn simple people of the red states, whereas it was considered one of the worst and most damaging things about him in the blue states."

"He had come upon an intractable obstacle which was going to take all of his skill, intelligence and strength to get over."