编者按：就在10月12日，美国总统辩论委员会公布了最后一场美国总统候选人辩论的主题，这场辩论将于19日举行。完全没有执政经验、又频频语出惊人、在党内及全美都饱受争议的特朗普，为何能一路过关斩将、直逼总统宝座呢？以下是欧亚集团（Eurasia Group）总裁伊恩·布雷默（Ian Bremmer）对此作出的分析。

Economics: Hollowing out of US middle and working class, globalization and US leadership on global issues isn't actually working for a large swathe of the American public. They want to go after the establishment; "kick the bums out," and Trump is an ample opportunity to do that.

Identity Politics: Obama is America's first black president, and I personally think that's pretty cool. But there's not much recognition that a lot of older white people feel they can no longer identify with what the United States today looks like. Younger Americans are much more multicultural--particularly Hispanic. They generally support immigration. They're much less religious. They're more likely to support drug legalization, oppose the death penalty, support gay marriage. Obama has empowered all of these views...while not having much time for those "clinging to their guns and their religion" as he put it. Trump is a big "screw you" to all of those people.

Social Media: Trump is a master. I'd say he's the world's most effective troll with a truly significant following. He had vastly more followers than any other Republican candidate (only Ben Carson was close). And the twitter folk tell me that despite having roughly as many followers as Hillary, he had 10x the impressions in the past month. That's the way more and more people getting their news...and it also is framed by the candidate himself (which the mainstream media then picks up on), rather than having the agenda set by someone else.