The US presidential electoral process begins well in advance of the election day, in some cases years. During this time, hopefuls compete to raise money, to win over the support of party leadership, its members and the political press. These candidates go from state to state, city to city, and district to district, courting donors and promoting their agenda. Individual campaigns set up headquarters at the national and state level, hire top strategists and recruit volunteers.

This has been a tradition for long.

The voting begins with the Iowa caucuses. It’s a meeting of residents who gather in designated locations, like school gymnasiums where voters publicly divide themselves into groups based on the candidate they support. Members of one group try to convince people in another group to join them. The key to winning Iowa is organisation -- having volunteers driving prospective voters to the caucus sites.

Although the caucuses tend to draw the most fervent supporters, winning or placing in Iowa is seen by the media as an indication of a candidate’s ability to carry a campaign across all 50 states.

Typically, the results of the caucus do not predict who will be the nominee, since most Iowa voters are white and tend to be more religious than in many other states. Nevertheless, it’s easier said than done to convince voters to leave their homes in the frigid Iowa winter and stand around for hours until the results are tallied.

Caucus participants are technically not choosing a presidential candidate but rather choosing delegates who will then represent them in voting for their candidate at the next convention level -- county, congressional district, and state where a similar process takes place. Delegates for the national convention are selected at the State and congressional district conventions. This does not happen in all 50 states though.

Other states have primaries, where voters mark a secret ballot to choose their candidate. The purpose is to narrow down the field of candidates, resulting in one Democratic candidate facing one Republican candidate. Weaker candidates who cannot build momentum drop out of the race during this process. These candidates then debate each other to start their election campaign.

The national party conventions are held after the last initial votes are cast in June -- for caucus or primary -- and spread over four days. These national conventions are not open to general public but only to delegates and party establishment, where the party platforms, sort of manifesto, are determined, and where delegates nominate the presidential and vice presidential nominees by state roll call.

The Democratic Party’s two contenders -- Bernie Sanders and Hillary Clinton -- are seasoned politicians with years of experience in Washington. One of them is going to win the nomination.

Meanwhile, on the Republican side, the presumptive nominee is Donald Trump, a billionaire businessman and reality tv star. The ascent of Trump is unprecedented in modern American politics, defying conventional wisdom. His popularity among Republican voters has driven the party ‘establishment’ into a tailspin. Based on fundraising and name recognition alone, Jeb Bush was headed to be the nominee, but his uninspiring campaign style could not compete with Trump’s fiery populism.

From the looks of it, the Republican Party establishment will have to accept Trump as the Grand Old Party (GOP) nominee, and many are not happy about it. There are 2,472 delegates to the Republican National Convention, and a candidate needs a simple majority comprising 1,237 or more delegates to win the nomination. The party establishment is largely not in favour of Trump, but they have no other option. Behind the scenes, party leaders and big donors have been desperate to find a safe and acceptable alternative to Trump. One possibility was the billionaire former governor and presidential nominee Mitt Romney but this trial balloon crashed to the ground.

While the Republican Party’s leadership is pretty much hostage to Trump, the convention might not go smoothly as we have seen before. For one thing, many are not convinced that Trump’s policy positions are in line with official party dogma; indeed, he’s been so erratic on the campaign trail that many insiders don’t actually know what his positions actually are. "The Trump campaign -- which had threatened to challenge delegate slates in several states over its own grievances -- will have to decide how it wants to approach such disputes while trying to unite the party and, perhaps most volatile, how to treat delegates who backed Cruz in some of his stronghold states," local media has reported.

Many are also frightened of Trump’s brand of unbridled populism. In fact, Trump’s negative polling numbers are through the roof, but high unfavourable ratings have done nothing to quell his support.

Again, the Trump card, if you will, is unprecedented.

His mastery of social media, particularly Twitter, is unique. His greatest strength, however, is his ability to control the press narrative. The amount of free press his campaign gets is estimated as high as $2 billion. For a candidate whose campaign has been largely self-financed, this extraordinary savings on campaign commercials and media buys is staggering. He also appears to have defanged two of the most powerful entities in the right wing circle of influence: Fox News and Talk Radio.

While his campaign has been described as a vile combination of hate, racism, bigotry and other divisive issues, he has also hit a nerve with blue collar voters who are bitter about manufacturing jobs being shipped overseas. Interestingly, Trump’s former clothing line was manufactured using cheap overseas labour but that doesn’t bother his supporters.

So far, the Republican Speaker Paul Ryan, who will be chairing the convention, says he’s, "just not ready" to endorse Trump.

On the other day, Trump fired back suggesting that he might try to remove Ryan Paul as convention chair altogether. Other seniors of the party like Mitt Romney, Jeb Bush, George Bush, and Lindsey Graham have said that they will not even attend the Convention because of Trump. This has created tremendous unease among establishment Republicans, who fear that Trump’s bombastic style and more radical pronouncements could result in an election day blowout in favour of the Democrats and fracture the party.

At this point, their one hope is to have some control over who will be Trump’s running mate.

A Boston University social science professor and expert on presidential politics, Tom Whalen, told the US news website, "Trump may be delivering the death blow to the American political party system -- he’s certainly rewriting the playbook." Former GOP President Ronald Reagan transformed the party platform into a more conservative one.

Republicans have traditionally taken a strong stand on issues like abortion and gay marriage. Although Trump’s views on these matters are still somewhat unclear, there’s no doubt that he has in the past sounded more left wing than the party he represents.

Interestingly, the ‘Trump card’ should be credited for taking on the system. He crushed over a dozen establishment candidates on both sides and challenged the Republican Party bigwigs leaving them helpless. Throughout his campaign he was himself -- an internationally recognised brand. What also scares political gurus is that Trump stands for nothing, and changes his positions on issues quite frequently. He is maddening and entertaining, frightening yet appealing.

Donald Trump might not win the general elections, but he will most probably win the Republican nomination, and as a result of which he will transform the Republican Party one way or the other. The Republican Party is at a historical crossroads. What the party will be after November remains to be seen. This, also in itself, is unprecedented.