Last modified on 26 September 2018, at 16:50

Game theory primary

Game theory becomes an important consideration in a crowded primary, such as the Republican nominating process for the 2016 presidential election. A total of 17 candidates (as of August 2015) vie for support, which requires considerations of game theory before criticizing rivals.

As of September 2015, only four of the 17 candidates have been willing to criticize Donald Trump, lest they lose potential support among supporters of Trump. Those four candidates are Rand Paul, Rick Perry, Carly Fiorina, and Lindsey Graham.[1] The first two perhaps hope to take support away from Donald Trump as a rival; the latter two perhaps hope to gain support from those who dislike Trump.

Who are rivals among the candidates?

Moderates compete with moderates for moderate voters, while conservatives compete with conservatives for conservative voters. But overly criticizing another candidate within one's sphere of support is risky.

The groupings below illustrate why Rand Paul and Carly Fiorina have been most vocal in criticizing Donald Trump:[2]

Social Conservative Moderate/Establishment Maverick
Mike Huckabee Jeb Bush Donald Trump
Ted Cruz Marco Rubio Ben Carson
Rick Santorum John Kasich Carly Fiorina - appeals to women
Bobby Jindal Chris Christie Rand Paul - appeals to men
Lindsey Graham
George Pataki

But Chris Christie and Marco Rubio are potential stalking horse candidates for Jeb Bush, perhaps hopeful that they will be picked as his V.P. So neither is likely to criticize Bush, and each will probably drop out and endorse him early.

Which Rivals Won't Criticize Each Other, and Why

Donald Trump and Chris Christie won't criticize each other because both are embarrassed by the collapse of Atlantic City, and their related roles in it.

Ted Cruz won't criticize Donald Trump because Cruz was not born in the United States, and Trump can cause a politician's approval rating to plummet by making this an issue, as Trump demonstrated by making it an issue against Obama.

Which Rivals Will Need to Criticize Each Other

The Texas primary is a must-win state for both Ted Cruz and Jeb Bush. Cruz needs to criticize Bush as being too liberal for Texas.

The NH primary is a must-win state for Donald Trump and Rand Paul, and hence it makes sense that Rand Paul would be most vocal in criticizing Trump.

Donald Trump needs to criticize Jeb Bush, the frontrunner for the Establishment that will surely increase its criticisms of Trump either publicly or privately.

Whom does Donald Trump help?

One theory, advanced at the Powerline blog, is that the candidacy by Donald Trump helps Jeb Bush.[3] But if Trump prevents Jeb Bush from winning in New Hampshire, which seems plausible, then Jeb Bush probably cannot win the nomination. Jeb Bush will fare poorly in Iowa and thus New Hampshire is a must-win state for him, but Trump seems poised to win New Hampshire.

Impact by Trump on Iowa

Iowa Republican primaries are less likely to support Trump, so he may not have much impact in that crucial first State.

NH primary

In the NH primary, mavericks running in one party, such as the Democratic Party, can weaken the support for a maverick running in the other party, such as the Republican Party, because Independent voters are allowed to vote in the primary of either party.


  2. Jim Gilmore is not shown because he did not qualify for the second 2016 presidential debate.

See also