Superlative form of staunch: most staunch.(adjective)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "staunchest" in a sentence
"Across the county there wasn't much interest in the school election until one of the nuttier churches put up some of the "staunchest" candidates."
"Interestingly, no one, not even the staunchest opponents of abortion rights, disputes this."
"However, Black Protestants have the highest degree of traditionalism and the highest level of religious activity and yet are the staunchest members of the Democratic coalition."