Whether Trump wins the presidential nomination is irrelevant. The damage is done and Republicans are left looking confused and weak. GOP leaders are trying to blame everyone but themselves, but they own this disaster.
If you listen to conservatives explain their "Stop Trump" movement they repeat the same claims; Trump is an impostor, an opportunist, or even a cancer on the GOP, but that is not a truthful interpretation of the rise of Trump. The truth is that Donald Trump is the natural evolution of a Republican strategy that stretches back to Richard Nixon.
In 1968, Nixon's Southern Strategy was a coalition that welcomed disaffected white southerners, many being uncompromising segregationists, into the party. The marriage of traditional "Country Club" Republicans including bankers and corporate leaders with poor rural segregationists was eventually going to cause the GOP to devour itself. It was obvious that Country Club Republicans had little in common with poor rural segregationists. Country Clubbers don't care about gun rights, prayer in school, or abortion.
This Southern Strategy has a great deal to do with the Republican push to "restore" power and control to state and local governments. The call for more state control and less political correctness is a euphemism for opposing the national trend toward inclusion and the enforcement of civil rights laws. Years ago the GOP abandoned it's role as a national party and adopted regional strategies where compromise became a dirty word and obstructionism was their only game plan.
In the process of executing Nixon's Southern Strategy, Republicans have succeeded in alienating Blacks, women, labor unions, Hispanics, Asians, the poor, gays, immigrants and those that believe in science, education, and equality, leaving the GOP with aging Fox fans, the very rich, and religious fundamentalists. Clearly, these are not the voting blocks needed to win a national election.
Republicans are in a state of denial, American society has changed drastically in recent decades but the GOP has refused to change with it. They stick with outdated social taboos and toxic prejudices and the longer they hold on to these policies against changing demographics the more severe and even permanent the damage will be.
These strategic mistakes along with Trump extremism will boost the Democratic turnout in the general election and could cause the Republicans to lose control of not only the Senate but also the House of Representatives. If that should happen, Republican Party leaders can have another secret meeting like the one they had in 2008, but this time they need to talk truthfully about inclusion and reaching out to all Americans or the alternative could be the eventual extinction of the GOP.