I feel compelled to respond to this.
Do not mourn our passing. I think one of two things will happen (and I'm an insider). Either a new, more authentic GOP will rise from the State parties and through the ashes of the national party. Or the two major parties will fold and you'll get a bunch of competing and interacting parties only without the freaky-deeky parliamentary coalition governments.
Conservatism is very much alive here in the US of A, we're just having something on identity crisis we have to mature through. For as ridiculous as Trump is, the Social Justice types are more ridiculous.
As I see it now, both ideologies are really at parity in long-term potential and both parties suffer from similar internal fractures.
What happens is in God's hands. We'll just proceed in the right as he has allowed us to see it, to paraphrase President Lincoln.
I fear for the future of the Republican party and conservatism in America as a whole with Trump. The American population in general is far too left-leaning to have a true conservative as a president at this point, but at least a centrist Republican as president would slow the rate of deterioration. Trump I feel will turn out to be a gift for the Democrats in the long-run, as Jimmy Carter was to the Republicans, maybe worse. This kind of craziness is completely unprecedented, especially considering what Trump and his many associates are under investigation for, and it will make Watergate look like nothing I have been led to believe. Constitutional crises are possible, maybe even likely.
As a Brit I am sad to see this happening to our closest ally and world leader.