Michael Bloomberg, the former New York City mayor with a net worth of $60 billion, now has a shot at being on the next debate stage in the Democratic presidential primary. With a donor base of one — himself — he did not reach the individual donor threshold that the Democratic National Committee (DNC) established last year in order to qualify. But last week, the DNC changed its rules, opening the door for Bloomberg to buy his way to a high enough polling threshold to participate.

It’s clear that DNC leadership is sometimes willing to engage in undemocratic maneuvering in the presidential primary process. But such efforts obscure something important about the nature of the Democratic Party: like the Republican Party, it is a bizarre hybrid of private political organization and public electoral system.

The United States has had a two-party system since the first half of the nineteenth century, and much ink has been spilled explaining why this is the case. Less ink, however, has been devoted to just how drastically the substance of US political parties has changed since then.

Wisconsin established the first direct party primary in 1905. Today, party primaries are so ubiquitous that it is hard to imagine a US political system without them. But we can’t overstate how bizarre the Wisconsin intervention was, and how drastically it changed the nature of our political parties. The primary race takes what is a core function of almost any other political party — candidate selection — and turns it into a state-regulated, public process.

The Socialist Party (SP) of the 1900s and 1910s was the last serious, nationwide, electorally successful third-party effort. The SP put more than a thousand candidates in office across all levels of government. The primary system was only just beginning when the party was in its heyday, but even by 1917, the vast majority of US states used primary races for some seats. Today, the system is nearly ubiquitous, and it is the exceptions that prove the rule.

In New York State, for example, special elections do not have a state-regulated primary. This has led to an unseemly practice in which politicians retire while in office, forcing a special election that enables the Democratic Party machine to pick a candidate. In heavily Democratic districts, this amounts to virtually noncompetitive elections. New York State judges are also elected without a public primary, a practice that has led the likes of the New York Times to endorse third-party judicial challengers.

The presidential primary is also filled with vestiges of the old system. This is the case because it is not regulated at the state level, as are all other seats (congressional seats are subject to state law, but the Constitution also allows the federal government to regulate them). So, as the primary system evolved over the course of the twentieth century, the presidential primary was immune. Indeed, the system of presidential primaries did not really take shape until the 1970s, and today, unpledged “superdelegates” still enjoy immense power within the party (although Bernie Sanders successfully maneuvered post-2016 to limit their power in the first round of voting at the presidential nominating convention). And, of course, with a snap of the fingers, the DNC can change the rules to let a billionaire on the debate stage.

As enraging as the exceptions are, they are just that: exceptions. For the vast majority of races in this country, party candidates are selected through a state-regulated, public primary system. For these thousands of races, Democratic Party organizations have no special technical or legal power with respect to candidate selection. This legal reality is what has enabled groups like the Democratic Socialists of America (DSA), the Working Families Party, and the Vermont Progressive Party to operate with substantial success “inside” of other party primaries. This legal reality is what makes Seth Ackerman’s much discussed “Blueprint for a New Party” a proposal worthy of the serious discussion it has generated.

The race for the US presidency is perhaps the highest stakes electoral race on the planet. As a consequence, what happens in that race generates strong impressions among the electorate about the society, our politics, our culture, and our electoral systems. Bloomberg can actually buy his way onto the debate stage with a simple rule change from an undemocratic party organization. But we should not let this high-salience, high-stakes exception obscure the legal reality that undergirds the Left’s emerging strategy for building electoral power in the US party system.

When Alexandria Ocasio-Cortez (AOC) ran her congressional primary race against Joe Crowley, there was nothing he could do, technically speaking, to stop her. There was no buying his way onto a debate stage. In fact, when AOC’s campaign orchestrated a debate, he did not show up.

The DNC’s machinations can be enraging, but the Left must stay the course. For the first time perhaps since the early-twentieth-century Socialist Party, we have a shot at real electoral power as a component of our movement. The primary system has allowed the likes of Alexandria Ocasio-Cortez, Julia Salazar, and Lee Carter to win elected office and move important projects. Let’s keep it up.