Illustration by Ella Apuntar

Iowa. Super Tuesday. Something about delegates. You might have missed the day in high school where they talked about how our elections work. 

This guide explains everything you need to know about how the U.S. selects its presidential candidates. Like the process it describes, it’s long, complicated, but ultimately worthwhile — we hope it helps you in the coming weeks. 


Both the Republican and Democratic parties select their nominees in the same basic manner. Based on the results of some form of popular vote, each state sends a certain number of representatives, or delegates, to a national convention where these delegates cast the final ballot for their party’s presidential nominee.

When all is said and done, whichever candidate wins a majority of these delegate votes wins the nomination. But just how these delegates are allocated per candidate, per state and per party is determined by a complicated cocktail of rules and traditions.


There are two main methods for translating votes into delegates: primaries and caucuses. Forty-six states and two U.S. territories hold primaries. In these states and territories, presidential candidates appear on ballots alongside other state and local line items. 

There are also two main types of delegates: district-level and at-large delegates. District-level delegates represent voters within county or big city borough-sized congressional districts (CDs), while at-large delegates represent voters statewide. 

So, when you vote for your preferred candidate, your vote is first tallied at the CD level. The share of votes each candidate wins within a CD determines the share of delegates they send to the national convention. The caveat is that in order to win any delegates at all, candidates have to reach a certain “viability” threshold of votes — about 15 percent in California CDs, for instance. 

Most but not all of Santa Cruz County falls inside California’s 20th CD, which spans as far north as Day Valley and as far south as the San Antonio Reservoir. This year, the 20th CD will be sending five delegates to the Democratic National Convention in Milwaukee. 

Once the CD tally is complete, votes are siphoned into a larger statewide pool. Here the process is essentially the same as in an individual congressional district, where the popular vote across the state determines how many at-large delegates the state sends per candidate.

Some state parties hold open primaries, meaning that anyone, regardless of their party affiliation, can vote for who becomes the party’s presidential candidate. Others hold closed primaries, where only registered party members can vote for their party’s nominee. There are also some areas of overlap between the two — California, for instance, has a “modified” closed primary, where both party members and unaffiliated voters can vote for a given party’s nominee if they request a special ballot.


If you were following the news coming out of Iowa two and a half weeks ago, you may have a sense of just how complicated the caucus process can be.

Think of them as primaries with more layers. Caucuses involve numerous neighborhood-sized precincts that decide how many delegates per candidate to send to a county convention. These county-level delegates then select delegates to send to a congressional district convention, who pick delegates to send to a state convention, who then pick delegates to send to the national convention.

Some state parties accomplish their initial, precinct-level vote via a simple ballot. But the Iowa Democratic Caucus makes things more complicated by turning each of 1,765 precinct meetings into a nightlong neighborhood crawl where campaign activists plead the merits of their candidates to bleachers full of onlookers and voters shuffle to and from various camps throughout the night. 

Aside from Iowa, Nevada, South Dakota and Wyoming also hold presidential caucuses, as well as the territories of American Samoa, Guam and the U.S. Virgin Islands. Kentucky Republicans hold a caucus too, but Kentucky Democrats don’t.

Why This System?

Although the U.S. Constitution offers some rules regarding the general election for the presidency, nowhere does it outline how parties should elect their candidates. Instead, rules governing primary elections and caucuses have been and remain largely controlled by the political parties — whether they be the Federalists and Democratic-Republicans of the 18th century or the Democrats and Republicans of today.

Arguably, these rules are also steeped in a long-standing U.S. tradition of skepticism toward popular rule. Similar to the rationale behind the electoral college, delegates allow political power to be more evenly distributed between urban and rural areas of the U.S. and place a certain measure of checks and balances on the electorate. So, if the citizens of the U.S. were to elect a candidate who later turned out to be unfit for the presidency, delegates could ostensibly vote against the will of their constituents. 

Local Delegate Talks Political Representation

In late July 2016, Pajaro Valley resident Jennifer Holm joined six other delegates representing California’s 20th congressional district at the Democratic National Convention in Philadelphia.

Holm, a registered nurse and an instructor at Cabrillo College, is decidedly not part of the party elite. Prior to becoming a delegate for Bernie Sanders, her political resume had been limited to a part-time labor organizer at the Watsonville Community Hospital. 

“I have a deep admiration for Senator Sanders,” Holm said. “But for me, the key point was fighting for the issues. Fighting for health care for everyone, no exclusions, and fighting for affordable college.”

But delegating became a political gateway for Holm. After the 2016 primary, she went on to represent Santa Cruz County as a California state delegate, and later became a trustee of the Pajaro Valley Unified School District. Holm said she won’t be vying for a Sanders pledge in this year’s primary, however.

“I had a chance to go and I went, and that gave me an opportunity to really talk and interact with our elected officials and other people who have power in the party,” Holm said. “This is an opportunity for other people to be advocates for candidates, and that power should be shared.”