As Popper argued, we need to make bold predictions, so we can learn from our mistakes. My prediction is that Trump will not win the Republican primaries for two reasons.
Firstly, while Trump is leading in the polls of the Republican primaries now, he is not close to a majority. Many voters support thirteen other candidates, seeing only one candidate can become the Republican candidate in the presidential elections, there is a strong incentive to not vote for those candidates that stand no chance of being that one candidate. This is very similar to Duverger’s principle, which states that in systems in which the winner takes all, there tend to be only two political parties. All votes for smaller parties are basically wasted votes, as they stand no chance of being elected into office, thus people will vote for their second or third preferred alternative.
Secondly,Black’s median voter theorem holds that in a one dimensional political spectrum, the outcome preferred by the median voter will get selected. The median voter is the voter who is exactly in the middle in terms of ideology. One dimensionality of the political spectrum means that voters judge candidates on one scale, for instance right or left, or conservative or progressive. The median voter in a one dimensional system decides who wins, because he is exactly in the middle. If indeed, as I expect, we end up with two viable candidates, Trump and whoever happens to be not Trump, we pretty much have such a one dimensional spectrum.
The problem for Trump is that he is incredibly radical, so very far away from the median voter. For example his remarks on women and immigrants, make it quite unlikely that the 43% of Republican voters who currently support non-white or female candidates would ever vote for him. So unless Rand Paul or Santorum happen to be the second candidate that is left over, as they are more extreme than Trump in certain ways, the second Republican candidate will be much closer to the median voter.
Something very similar happened in Canada recently. Canada also has a first-past-the-post system, which means that the parliamentary candidate with the most votes in a district (or riding as the Canadians call it) wins. In order to vote the Conservative Party out off office, many people who preferred the National Democratic Party (NDP), strategically voted for the Liberals, because the Liberals were marginally bigger than the NDP, so they stood the best chance to defeat the Conservatives. I think Trump will suffer the exact same fate as the NDP.
This also means that all the other candidates should think about whom they attack. Stealing voters from Trump might be much harder than stealing them from other candidates. Attack those other candidates to decrease their support might be better than attacking Trump, if indeed the biggest candidate who is not Trump will win the Republican primaries.
Bottom Line: Duverger and Black combined spell bad tidings for Trump. Trump will not win the Republican primaries, as he is too radical. As long as he is running against many other candidates, he has a plurality, but as soon as the electoral system forces other candidates out of the race, many of the former supporters of ex-candidates will support whoever is not Trump.
P.S. Was I wrong…