Two weeks ago, Donald Trump and the Republican Party pulled even in the polls with Hillary Clinton and the Democrats. Pretty much everything has gone wrong for Trump since then. The Republicans have fallen from +200 to +250 to win the 2016 US presidential election; Clinton and the Democrats are up from –260 to –325.
The Democratic Party is enjoying the standard “bounce” coming out of last week's convention; however, Trump has added to his problems by making inflammatory comments about the Muslim parents of a fallen American soldier. Trump also made the mistake of tweeting a picture showing him about to eat a piece of Kentucky Fried Chicken – with a knife and fork. On his private jet.
There are still three months to go before the election, but unless Clinton makes a major faux pas, or outside forces (terrorists, Russian hackers) intervene, things are not likely to improve from here for the GOP. In appealing to his base, Trump has split the Republican Party in two, alienating people who would otherwise be supporting his presidential campaign. We're likely to see more of these disenfranchised Republicans come out and publicly endorse Clinton, after the Congressional primaries are over.