http://www.slate.com/articles/news_and_politics/politics/2015/06/jeb_bush_s_trip_to_europe_the_republican_candidate_traveled_to_berlin_to.html

Every presidential candidate must perform certain compulsory exercises. One is that you must write a book. Another is that you must make a high-profile trip overseas, most likely to Europe or Israel. Candidates travel to foreign capitals so that they can look presidential. They wear their best suit, shake hands resolutely, and sit at long tables with good posture. We see the president shaking these hands and sitting at these tables a lot of the time, so if a candidate dresses up and plays president, we might think he’s fit for the job. These trips also allow the candidates to claim greater foreign policy wisdom. So, for example, if you ask Wisconsin Gov. Scott Walker about foreign policy, he will tell you about his recent trip to Israel. And it works for him. Here’s the first paragraph of a Des Moines Register story: “Fresh off a trip to Israel, Wisconsin Gov. Scott Walker told a crowd in West Des Moines that what he saw there only reaffirms his belief that America should take a stronger stance against terrorism.”