When political historians look back on the 2016 presidential contest, they'll likely consider May 4th to the present as the decisive period. On May 4th, Donald Trump won the Indiana Republican primary; his last competitor, Ted Cruz, dropped out; and the press labeled Trump the presumptive GOP candidate. A week later, Trump got a polls "bump" and was effectively tied with Hillary Clinton. Then Donald lost his mojo.
At the moment, Hillary Clinton leads Donald Trump by 7.5 percent in the Huffington Post Poll of Polls and the spread increases daily. Clinton also leads in fundraising and is generally credited with having a more effective campaign. Clinton was the first to run TV ads in critical swing states.
What happened to Trump? How did he squander his advantage?
Donald didn't adjust. It's a political axiom that it takes different tactics to win a general election for president than it does to win a primary election -- it's one thing to win over Party partisans and quite another to win over the general population. Trump didn't recognize this and, therefore, kept running the same style of campaign and employing the same tactics.
Trump doesn't have a campaign infrastructure because he hasn't raised the money necessary. A recent Huffington Post article said that Trump only has 70 paid staff members compared to Clinton's 732. The New York Times reported that, in this 45 day period, Trump has yet to run a TV ad; Clinton and surrogates have spent $25.5 M on ads.
A Time Magazine article observed: "[Trump] has planned no big fundraising blitz or major TV ad campaign for the fall. He has little interest in the latest advances in data analysis or digital strategy. And despite a personal fortune that runs into the billions, Trump does not want to hire a big staff in the states to get out the vote and to court local leaders. He prefers to talk to reporters and surrogates himself, betting on his own gut and guile. Trump's campaign is entirely ad hoc. It's a guerilla operation built on the concept of mass communication."
On June 20th, Trump fired his campaign manager, Corey Lewandowski.
Donald lost focus. For the first three weeks after he won the GOP nomination, Trump kept doing what he had been doing -- emphasizing key Trump issues such as immigration and attacking Hillary Clinton. Then he lost focus. On May 27th, a Federal judge in a civil case involving Trump "University" ordered the depositions made public. The next day, Trump used a California campaign speech to attack the judge, accusing him of bias because the judge's parents emigrated from Mexico.
When asked about his comments, Trump doubled down. In a May 31st press conference Trump repeated his charges against the judge and attacked the press, in general.
On June 2nd, Hillary Clinton gave what she had labeled a foreign policy speech. It was a prolonged attack on Trump. Clinton declared Trump temperamentally unfit to be President. She declared his ideas as "dangerously incoherent," adding that they consisted of "a series of bizarre rants, personal feuds, and outright lies." Trump was so obsessed with the "Trump University" case that he didn't respond to Clinton.
Donald blew his opportunity to get back on course. Presidential campaigns take a long time and external events usually present an opportunity for course correction. On June 12th there was a horrendous shooting spree in an Orlando gay nightclub. Because the killer was an American Muslim, the event was an opportunity for Trump to trumpet his signature issues: domestic security, immigration reform, and Muslim ban.
On June 12th Trump tweeted: "Appreciate the congrats for being right on radical Islamic terrorism." On June 13th, Trump responded with a speech so over-the-top that it was universally panned. Politico reported a spot poll: 51 percent of respondents did not like the way Trump responded to the Orlando massacre, while only 25 percent approved.
Donald failed to united Republicans. After he secured the nomination, Trump had a chance to unite Republicans. He didn't do this. He got a lukewarm endorsement from Mitch McConnell and Paul Ryan and did not garner the support of Republican elders such as George W. Bush and Mitt Romney.