It is very unlikely that our two parties will ever agree on any important issue enough, or ingnore such an issue enough to bring about one of their downfalls.
At first blush, I'd agree with you. But I do think the Dems have taken a fatal plunge down a path. Either they get resurrected by the insurging of different coalitions and parties, or they drown under the weight of their own liberal hubris and actions. Sometimes I suspect this Closseau-ian ploy is exactly what Move-On has in mind -- "and now offering.. the NEW, new Democrat party..." which perhaps might decide to leave America, move to some third world country and show the world how socialism, properly done, and with funds collected by the local leading tyrant.. can work!
History does repeat itself; sometimes, in not directly predictable patterns such as your excellent recitation of history provided.
Republicans were very unhappy after Nixon lost in 1960. After all, Ike had been a very successful and popular Republican President. Nixon should have won just as Bush 41 did after 8 years of a popular and successful Reagan.
Conservatives were very unhappy after the loss to Kennedy. If they were going to get beat with a moderate NIXON, the right came to the conclusion they might as well lose with a real Conservative like Goldwater. And many were certain that if the voters just got the Conservative message they would vote for a real Conservative. Over and over they said we need a choice not an echo. They believed that voters would not support a Democrat clone like NIXON, but they would come out for a genuine conservative. After Nixon lost the Governorship of California to Brown in 1962, Conservatives were certain of one thing... They needed to kick out the RINOS and then win a real victory. Massive victory was just a year of purity away.... UH HUHHH! There are many Democrats who believe that only a real true blue liberal can win. No more DINOs for the left.. they want a true believer.
Goldwater of course got the grass roots behind him. He won the 1964 nomination in a rout. Party professionals knew what was going to happen but the rank and file believed that Barry would sweep to victory ... Once the nation really saw what conservatism was, "In their heart you know he's right!" is what they preached." The truth was most voters agreed with, "In their guts they know he's nuts."
We know the result...Goldwater suffered a terrible defeat. He was painted as an extremist and responded to that charge by claiming in his acceptance speech that "Extremism in the defense of liberty is no vice." That was real dumb city but the base was ecstatic with their choice not an echo.
So what happened after the Goldwater debacle? Did the Republican party fold? Certainly not. The far right was devastated by the magnitude of the Goldwater loss. The moderates and centrists came back to take over the Republican party. And the excesses of the total rule of LBJ and the left, gave the presidency to Richard Nixon in 1968.
Right now the Democrats are walking off the mirror image of the Goldwater plank. They are going as far left as Goldwater went right. But after a loss the moderates will be back to take over the Demoratic party.
Hillary and Clinton know better. They have tried to move to the center where victory lies. Bill tried to help her move to the center by publicizing his friendship with the Bush family. That resulted in the polls showing Hillary in trouble with the base... So she and Bill MUST ATTACK Bush to hold the far left. Every time the far left sees Clinton with Bush 41 they go ballistic.
By first being a friend to the Bushes and then turning on them, the Clinton's have proved themselves to be untrustworthy. Moderates put great faith in trustworthiness. The moderates are not ideological. That why they are swing voters. They vote for people they believe they can trust. Some times that is a leftists sometimes it is someone on the right. The key is trustworhtyness. The Bush-Bill Clinton friendship had to be a plot planned in Karl Roves fertile brain. It put Bill and Hillary in a no win situation. To hold the base they have to sacrifice what it takes to win the center. But with out the base she can't win the primary. And with out the center she can not win the general election.
So the Democrats are about where the Republicans were in 1962. The base will not stand for anything other than total opposition to Republicans. They want a choice not an echo. The more dirty tricks pulled on Republicans the better the Democratic base likes it and the more of the center the Democrats lose. It is a fact. The centrists who hold the balance of power will not support untrustworthy obstructionists who turn on friends.
But this will not end the Democratic party any more than the loss of Barry Goldwater did to the Republicans. Once the left suffers more defeats they will become so hungry for victory they will embrace moderate Democrats who can win. Their hatred of all things Republican will cause them to embrace a moderate Democrat.
The pattern repeats many times.
Harry Truman said it best. Harry said, "The only things new under the political sun is the history you don't know."