This is an excellent description of what has happened in 2016: http://www.vox.com/2016/7/28/12306780/democratic-convention-speeches-patriotism-rhetoric
The Republican party (largely because it is an older and whiter party) has traditionally laid claim to........well.......tradition. That America is great and (as Reagan said) a shining city on the hill where people want to come and we are the best and the brightest and the greatest.
That the GOP can claim this message has stuck in the craw of most Democrats. The party has (at least since 1968) appealed to many who have been underserved by "tradition" (women, minorities, gays, the poor) and don't enjoy the idea that America is great, but no so great to them.
Enter Donald Trump.
The message from the 2016 GOP Convention in Cleveland was well summed up by Trump -- trust me, I am great, America sucks, we are stupid, we always lose, be afraid, be very afraid. Everything about America sucks and you should be terrified to step out your door any day of the week. Only I, Donald Trump, can make America great again (cuz it sucks right now).
By going with this message, Trump has ceded the more traditional GOP message of love of country to the Dems. And who do the Dems have to ram that message home? Bill Clinton -- raised very poor by a mom who abandoned him for years. Joe Biden - raised lower middle class in Scranton, PA. Barack Obama - raised as a mixed race child by his white grandparents and white single mom.
These gentlemen can tell a very compelling story of loving America and loving the people at the lower end of the economic spectrum, because they grew up there.
The Republicans? Well, they can still hang tight to the hope that they will get enormous tax cuts for the rich (most of whom personally hate Trump, but they still want his proposed ridiculous $34 trillion giveaway) and enjoy the fact that maybe they can get every scared, disaffected, poor and uneducated white person in the nation to vote Trump and that will be good enough for now. The coalition of the frightened, uneducated, racist and poor may be enough to win. But winning to what end? Once this coalition is in power, what will they hope to achieve? Will dirty jokes become legal again? Will white people get more power? Will all fanatics just stop being fanatics?
Congrats, Republican Party, you have lost the one thing you were really good at -- being optimistic and patriotic. Your new pitch? "We will keep Timofey Mozgov's taxes low!" or "David Duke seems to like us!"??