high ground

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A position of superiority over others, especially competitors or opponents.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun countable or uncountable Used other than as an idiom: see high,‎ ground.
• noun idiomatic A position of advantage or superiority in a conflict or competition.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a position of superiority over opponents or competitors