Not a political thread - but why do politicians plagiarize so much?

Politicians of all political persuasions seem to get caught up in this.

Ben Carson is the most recently unveiled plagiarist, in a book in which he writes about his experiences plagiarizing at college.

http://www.salon.com/2015/01/07/conservative_hero_ben_carson_hit_with_plagiarism_scandal/

Is it sloppy work by underpaid ghost writers? Ignorance of the power of plagiarism checkers?

Politicians probably don’t plagiarize more than others…being out in the public with so many watching them they probably just get caught quicker doing it. Too, most politicians probably have staffers and operatives write their speeches and position papers for them. Politicians don’t have pens in their hands often writing speeches…they use their hands mostly for shaking hands, slapping backs, and grabbing cash.