Donald Trump has announced that he “won’t bother” with Thursday’s Republican debate — the last one before Monday’s Iowa caucuses. It’s certainly not the norm for a leading candidate to bail out on a party event just as primary season is about to begin. But Trump’s decision not to participate Thursday is especially weird because the debate is hosted by Fox News.

In the school of thought that defines parties as networks of actors who have a common purpose, Fox News is easily included as part of the GOP — not just as a sympathetic news outlet, but as a member of the party coalition. So we have a situation where the Republican Party’s polling front-runner is openly feuding with its biggest media outlet. This is not how parties are supposed to work according to many political scientists.

Trump, of course, has already sparred verbally with Fox anchor Megyn Kelly, who moderated the first Republican debate back in August. The incident was one of Trump’s early run-ins with the informal GOP establishment, including media figures such as Kelly and Erick Erickson, who decided to bar Trump from an event the next weekend. But those dust-ups passed quickly. This time, the conflict has intensified, with Trump remarking that Kelly is “not very good at what she does” and withdrawing from the debate.

Pundits and political scientists have been debating for some time who controls presidential nominations, as well as what the 2016 race tells us about that question. The main argument has been whether Trump’s consistent success in the polls undercuts the theory that networked party elites can control the process, winnowing out undesirable candidates and promoting preferred ones.

Now that Trump has been denounced by one major conservative media outlet, National Review, and continued a feud with another, what does this mean for party politics? One of the steadfast claims of the “Party Decides” school is that different types of actors in the coalition don’t really play distinct roles. The density of the networks between, say, official party organizations (like the Iowa Republican Party) and ideological interest groups (like the American Conservative Union) means that these groups share staff and funders, and their overall goals and functions within the party end up being pretty similar: to work toward common policy goals and nominate amenable candidates.

But, although it is sometimes depicted that way, the “Party Decides” school doesn’t represent a consensus in political science about what parties are or how they work. Most recently, Ray LaRaja and Brian Schaffner have argued that formal party organizations make different decisions about which candidates to fund, for example, than do interest groups. In other words, there are other political scientists who think different party actors have different incentives and capacities.

The unfolding conflict between Fox News and Trump may illustrate the implications of loosely configured parties that operate by informal rules. Fox News and National Review may play critical roles in disseminating conservative ideas and promoting conservative causes. But they don’t seem to be very effective in winnowing out a candidate who can generate plenty of media coverage on his own.

Much of the debate over “The Party Decides” has been about its predictive power, but perhaps it is time to look at its implications. If parties really operate without much hierarchy or many formal rules, then we shouldn’t be surprised that they are highly susceptible, under the right circumstances, to hostile takeovers by outsider candidates. And if Trump’s decision to sit out the debate brings him more attention and raises his standing in the polls — as the trend seems to have been — then it will be another piece of evidence that sometimes primary voters decide on their own.

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