The moment the fatal wounds were afflicted.

How did we end up with two ancient, disliked men being advanced by their parties?

Well, we ended up here as the Democrats quit believing in democracy, favoring rule by the courts, until the courts decided they believed in democracy, and because both parties lied to their rank and file, working class, constituents for a period of fifty years.

We've dealt with this before.

However, it can nearly be determined with precision.

The date of the wounds were:

• January 22, 1973

That's the date the United States Supreme Court issued the Roe v. Wade decision, replacing its judgment for that of state legislatures. As the dissent noted:

I find nothing in the language or history of the Constitution to support the Court's judgment. The Court simply fashions and announces a new constitutional right for pregnant women and, with scarcely any reason or authority for its action, invests that right with sufficient substance to override most existing state abortion statutes. The upshot is that the people and the legislatures of the 50 States are constitutionally disentitled to weigh the relative importance of the continued existence and development of the fetus, on the one hand, against a spectrum of possible impacts on the woman, on the other hand. As an exercise of raw judicial power, the Court perhaps has authority to do what it does today; but, in my view, its judgment is an improvident and extravagant exercise of the power of judicial review that the Constitution extends to this Court.

And Democrats concluded they didn't really need to persuade voters anymore, the Courts would impose a new liberal regime on the besotted and benighted public without their participation.

And:

• July 17, 1980.

That's the date that the GOP nominated Ronald Reagan for President. Reagan would go on to use the Southern Strategy to draw in Southern (and Rust Belt) Democrats who had lied to as the post World War Two economic prosperity collapsed. Thing is, the GOP didn't really listen to their concerns, just as the Democrats had quit doing. 

Seven years in which we went from two functioning political parties and put them on the path to being pure machines, breaking what they claimed to serve.