INDIANAPOLIS, Ind. (WOWO): The strength of Donald Trump and Ben Carson has upended conventional wisdom about the presidential race. But in other countries, their campaigns wouldn't be that unusual.

Outside the U-S, it's common for not only doctors and businessmen, but economists, novelists, and other political outsiders to mount presidential campaigns with no prior political experience.

The trend has been particularly notable in Eastern Europe, where leading anti-Soviet dissidents, from Czech playwright Vaclav Havel to Lithuanian music professor Vytautas Landsbergis, were the natural choices to lead their countries after the fall of Communism. But Carson's fellow doctors are the current leaders of seven countries. And Guatemala elected comedian Jimmy Morales president in September, in a backlash against a government corruption scandal.

I-U Institute of European Studies director Timothy Hellwig suggests outsiders have had a tougher road in the U-S because the primaries act as a gatekeeper, giving the parties and donors more say over the process. And he speculates the diversity of the American electorate has made it harder than in other countries to win elections by appealing to a narrow base, though he says Trump and Carson's success may demonstrate it's possible in the U-S as well.