Often those with political clout seem to display a sense of aversion towards public apologies, however examples like this show apologies can be and often are remarkably effective.

http://www.nbcnews.com/video/nbc-news/51026118#51026118

http://www.washingtonpost.com/blogs/worldviews/wp/2013/03/22/yes-netanyahus-apology-to-turkey-is-a-very-big-deal/