I am on the Bucks County Republican Committee. I'll summarize my observations on why Trump is the party nominee.
1. Many Americans feel that both the traditional Democratic and Republican parties have failed them. On the left, the feeling of a failed party spawned the Occupy Movement. On the right, the same feeling spawned the Tea Party Movement. Additionally, there are millions of voters on both sides who might not belong to either movement, but are sympathetic to the specific complaints and focal points of each/either of these movements. These folks are also fed up with the way both parties have been running the country. The fed-up folks on the left, and the Occupiers followed Bernie Sanders. The fed-up folks on the right and the Tea Partiers followed Trump. Basically, the "establishment" candidates were not popular this election cycle because people want real change.
2. Both Trump and Sanders use an unscripted mode of delivering speeches and conducting interviews. Because Americans are accustomed to hearing scripted, polished modes of speech from candidates and sitting politicians who have lost their trust over the last couple of decades, scripted and polished have become synonymous with un- trustworthiness and lies. Unscripted is not only getting voters' attention because its a new and different way to communicate on the political stage, but because it is the opposite of scripted, it has become synonymous with truth and honesty. So voters are drawn to Trump and Sanders because of their unscripted delivery.
3. Sadly for Sanders--and I will admit that I could possibly have voted for him in a general election--the Hillary machine was already well-funded and well-established politically. Throw in the fact that too many of the delegates had already pledged support for Hillary before the race even really started, and Sanders didn't stand a chance. Although I think if he had done a better job getting out the vote, he would be in a position to challenge Hillary at the Democratic convention. I'm afraid there will be enough angry Sanders voters who will show and attempt to disrupt the Democratic convention, and the powers that be in the DNC and Philadelphia itself are preparing for that possible threat.
4. Trump is, and always has been a strong-willed, take-no-bullshit guy. His full-frontal approach to just about everything he does stands in stark contrast to the uncommitted tone of politicians in both parties, especially the gentleness of Obama's approach. Yes, it is true that gentleness is often mistaken for weakness, but in the case of Obama, his detractors will point to policy failures that support their perception of him as weak. Former fed-up Democrat voters have expressed this perception and changed parties in order to vote for Trump.
5. Trump’s platform contains more meat and less fluff than the other Republican candidates in the field. Trump’s platform also focuses attention on the core issues in America. No, I did not review ALL of the GOP candidates’ websites, just those that made it to the final 4. Trump’s platform contains actual actionable plans. Cruz, Rubio, Kasich, and Carson posted much weaker, fluffier content to their websites. Cruz and Rubio spent to much time telling us what they did and didn’t vote for in Senate. Kasich spent too much time telling us what he did in Ohio, and expecting us to think those solutions would scale up on a national level. Carson was too much about what he believed, and what he would support.
6. People are sick and tired of political correctness and social justice warriors guiding various national conversations, and creating an atmosphere where free speech is stymied. They are also fed up with having ideas from the right classified ignorant, bigoted, unfair, etc. Trump stands up to the name-calling, and his supporters see him as someone who will make it safe to have open honest conversation about a whole range of issues that we currently tip-toe around.
7. Hillary’s history of being involved in scandals has pushed some voters in Trump’s direction. Many people—women especially--look at the fact that Hillary stayed married to Bill through the sex scandals and they think she did it in order to improve her own political career. They think she whored herself out in exchange for political power. Additionally, there is still lingering doubt about Benghazi, and whether Hillary’s State Department did anything to contribute to outcome either through action or inaction. But more than anything, Hillary stands out head and shoulders above everyone else as the career politician in the room. She represents the establishment that so many voters want to get away from.
8. Trump has a long record as a successful business man. People admire him for this, and they think that his business success will translate into a successful presidency. Even the bankruptcies make him look even stronger because he was able to pick himself up, dust himself off, and do even better after each bankruptcy—and that takes a strong character and good business acumen.
There has been lots of switching parties leading up to primaries and caucuses in each state. Some states gained more Republican voters, some states gained more Democrat voters. As of the voter registration deadline here in Pennsylvania, at least 128,000 voters statewide had changed their registration since Jan. 1 to join the Republican party. In that same timeframe 86,500 voters switched to the Democratic party.