After an overwhelming electoral landslide loss in the 2012 general election, the Republican party went through an "autopsy". Dubbed the "growth and opportunity project" it listed several points on how the party should work on expanding its reach. They aimed to work on becoming a more favorable party for hispanic voters, LGBT community, African Americans, single women, millennials and several other demographics that voted for the democrats that November. But that was 2012 and this is 2016.
Meet Donald Trump
The brash billionaire businessman from New York came out of nowhere last July and lit that GOP autopsy on fire. From his comments about comparing undocumented immigrants to rapists to banning non american Muslims from entering the United States, he has not only alienated Democrats, but also people in his own party. Various online polls show just how unpopular he would be facing Hillary Clinton or Bernie Sanders in the general election.
The Republican party, recognizing this fact is quietly determined to deny him the nomination at the party's convention in July. Even if Donald Trump walks in the convention with the most delegates and votes. Ideally, they'd like to see someone who's more favorable among the establishment and the general election voters to face Hillary or Bernie this fall.
I believe this would be a massive mistake. Denying the voice of a large chunk of the voting base would alienate those voters that turned out in the primary to vote for Donald Trump. Those same voters are so angry at the Republican establishment that they would most likely abandon the GOP and give up on the political process. Whoever the Republican nominee is, they would desperately need the Trump voters to back the candidate if they wants a realistic shot at winning back the White House.
On the other hand, a Trump nominee would be a disaster itself. He would be the most unpopular candidate to become the GOP nominee since Gerald Ford in 1976. Here is just a look at how various demographic groups view him
Among swing voters
64% unfavorable among Independent voters
68% unfavorable among white women
74% unfavorable among white college graduates
Among Democratic leaning groups
75% unfavorable among moderates
80% unfavorable among 18-34 aged voters
80% unfavorable among African Americans
85% unfavorable among Hispanic Americans
Among Republican leaning groups
52% unfavorable among non college educated whites
53% unfavorable among conservatives
56% unfavorable among white evangelical protestants
51% unfavorable among white Americans.
Source
It seems like whatever path you choose, the Republican party would have a tough time to unite all its voters. After the convention ends, there would only be three months left till the general election. Whoever comes out of that convention in July the GOP is going to have an incredibly difficult task to come up with a nominee that unites everybody to beat Hillary Clinton or Bernie Sanders. It's a lose-lose situation.