Donald Trump claims he's treated unfairly a whole lot. Here are just a few of the times he said he wasn't getting his due. (Peter Stevenson/The Washington Post)

Donald Trump has been complaining about unfair treatment since, well, pretty much the beginning of his campaign. And it’s getting to be an everyday thing.

The first round of complaints came in August of last year, and they were directed at one person: Fox News anchor Megyn Kelly. Trump alleged that Kelly asked him “unfair” questions at the first Republican candidates’ debate on Aug. 6. And once they started, the insults came thick and fast.

Trump’s complaints picked back up when the subject of the GOP “loyalty pledge,” asking candidates to promise they wouldn’t run as independents in the general election in November, became a hot topic last fall. Trump repeatedly cast the pledge as a two-way bargain – and from the beginning, implied that the Republican Party, the media and the Republican National Committee in particular, were treating him differently from the other candidates.

And then it started to get weird.

Trump's fixation with Kelly and her “unfair” questions went to a whole new — and more personal — level. And other groups were swept up in the unfairness mania.

The media as a whole. The Washington Post in particular. Protesters at his rallies. Anyone who saw wrongdoing in the video footage of campaign manager Corey Lewandowski grabbing reporter Michelle Fields.

But the accusations of unfairness took on a different tone as the campaign moved into April. In the past few weeks — at the same time Ted Cruz has made huge gains courting unpledged delegates — Trump’s target has become the Republican primary system and, in a broader sense, the American political system as a whole.

He calls it “rigged,” “crooked” and “phony.” He goes after individual states, the GOP as a whole, and RNC Chairman Reince Priebus. And it seems to serve dual purposes for the New York billionaire.

First, it’s what the voters want. As The Fix has written many times before, the 2016 campaign has revealed, more than anything, the high number of American voters who are dissatisfied with American politics as usual. Frustrated liberals have flocked to Sen. Bernie Sanders of Vermont, while frustrated conservatives seem to have lined up for Trump. They’ve certainly made his rallies packed affairs. So the more Trump rants about the system and how it’s set up to protect the party establishment, the more it resonates with his base.

Second, it applies pressure on the party. Say Trump gets to July and fails to get the Republican nomination on the first ballot at the Republican National Convention. At that point, the party makes a decision between giving the nod to Trump and prompting a possible uproar among Trump backers. And the more Trump reinforces that the system is rigged, the more that uproar will loom.

What’s more, as he hinted last fall when pressed on the (pretty much meaningless) GOP loyalty pledge, he might run as an independent if he feels the party was unfair to him. And he certainly feels the party is being unfair to him.