"Political scientists have been studying the question of campaign promises for almost 50 years, and the results are remarkably consistent. Most of the literature suggests that presidents make at least a “good faith” effort to keep an average of about two-thirds of their campaign promises [...]
Examining more than 500 promises President Obama made during his two presidential campaigns, PolitiFact finds that he has fully kept or reached some compromise on 70 percent of them. Similarly, Republican leaders made, by PolitiFact’s count, 53 promises before taking over Congress in 2010; 68 percent of these have been partially or fully kept."Durchaus überraschend wie ich finde.