Honestly this is pretty close.
I'd say though just as much, if not more than the collapse of faith in government that Prohibition was, there are two other pillars that killed the movement.
Okay. Firstly, Japhy, before we get into the main reply, I'll have to say that although you did manage to hit on some key truths, there are also some things that are best not left uncorrected.
On the first hand is what one might refer to as the "High Progressiveism" of the Wilson years. Specifically, the application of Progressive thought, not in his first term but in the rather nasty second term.
Great figures in the movement and highly respectable men who agreed with the ideology: Baruch, Hoover, Garfield, McAdoo, Daniels, Lansing, Baker and Palmer under Wilson, as his "War Cabinet" pretty much see the use of Progressive ideology (That is the application of scientific methods to enact reform) turned on the American people in the name of winning the war and securing the peace. Americans are thrown in prison for questioning things, businesses are practically nationalized for the war effort without a fair shake for the workers, and of course thousands and thousands of young American boys are sent to die for some sort of Progressive Foreign Policy Wet Dream.
Firstly, I've already pointed this fact out on several occasions, but no, Japhy, Progressivism was not *all* about "scientific methods" to reform: yes, it may be true that it was a not-insignificant school of thought within the Progressive movement, especially in the early days, but it was hardly the only one, and wasn't even all *that* dominant, for the most part: reformist ideals came from several different viewpoints(such as the religious one espoused by William Jennings Bryan, or the quasi-socialism of Robert LaFollette).
Also, Woodrow Wilson, for all his campaigning, was really only as Progressive about as much as what he thought would gain him more votes in the elections. And your (at least implied) contention that Wilson's throwing people in jail for being against our entry into World War I was somehow "Progressive" is simply unsupportable, especially given that so many of those who wanted us to stay out of the war were themselves Progressives of one stripe or the other(like Jeannette Rankin, for example. She was so devoted to pacifism that she didn't want us to draft anyone for WWII, either).
Then of course, as Hades said, there's the farce of Prohibition, the enacting of a Major Progressive Goal, with massive, broad support in the movement across party lines, more or less shreds for a lot of Americans the idea that the government can know whats best, and that these solutions are worth standing for.
There is some truth to this, yes, although Prohibition did enjoy some support outside of the Progressive circles, as well.(namely, hardcore anti-Catholic elements, who mainly targeted Irish and Italian immigrants.).
The closest the United States ever comes to some sort of Proto-Fascism is achieved entirely wrapped up in the flag and the ideology of Progressivsm. Its a major blow that can't be ignored.
Now this is just plain biased, considering that Wilson wasn't all that Progressive to begin with.
And thirdly, the final blow one has is the 1928-1932 period. In 1928 Herbert Hoover --- a Bull Moose supporter in 1912, if not someone who actively switched his party allegiance --- goes up against Al Smith, who finally gets his chance to run his wet, modernist, Progressive campaign. And in the face of this Progressive vs Progressive race, we see the collapse of the economy, and the outright bungled economic aid and reforms of the Hoover years.
The Great Depression was a crisis far greater than the Panic of 1907 or the Post-War recession. And the application of 1912-style Progressive reforms by Hoover, tied with his inability to make an impact on the general feeling of the country showed the weaknesses of ideological progressiveness. At that point the door opened to something new, which while being based in a large part on the old style Progressivism of the 1900-1932 era was inherently different in philosophy, intent and action: New Deal Liberalism.
And, no, Japhy, the Herbert Hoover of 1928 wasn't terribly Progressive, either; perhaps he might have been in 1912, but not so much in 1928(although, to his credit, he did have a little sympathy towards Civil Rights, something that even quite a few Progressives had largely ignored).
There are of course other minor problems with the system of thought: As others say the need to be as big a tent as possible. The encapsulation of a lot of rather negative "Scientific Reform Movements" under the tent such as the Eugenicsts and fun groups like the KKK and the American Legion. The failure of most of the movement to recognize that minorities and ethnic groups were deserving of equal rights and their own culture. The attempts before 1920 to unite with the Populist movement remnants and after 1920 to unite with Marxism. The clash of varied strains of liberalism against each other, and against the Conservatives in the movement that sought to use it as a tool to lessen the pressure that was empowering Populism and Socialism. The turning against each other that was the 1912 election. The fact that Robert La Follette was seen by many and may very well have been suffering from some sort of mental disorder. All come to mind.
While you do, in fact, kind of overstate the failure of the Progressives in regards to equal rights, you are actually largely correct here, otherwise.
Yes, it is a term in very common use today (By self-hating Liberals)
Erm, this is more complicated than that, Japhy. (Not that it isn't a problem, though, but.....)
.....and in 1948/1952 one has a party run under the banner. But in neither case are we dealing with groups that are representative of that Pre-1933 political movement.
This is *largely* true, but some of the basic tenets and values of the LaFollettians and other leftist classical Progressives did provide some of the roots for today's movement.
What we are dealing with at various points is more or less manifestations of New Deal Liberalism pushing an all-or-nothing program, or less generously, their sore-loser candidate, or some Reformed New Dealism/Non-radical New Leftism/Social Justice style political ideology of bog-standard American Liberalism that has been on the outs in Democratic Politics since 1992 or 1972.
New Deal Liberalism also had a good deal of it's roots in Progressivism, though, that's another thing.
So the question becomes, are we talking about keeping Progressivism of the 1900-1932 variety going, are we talking about the 1948 party somehow continuing, or are we talking about New Deal Progressivism surviving the 1960's and beyond as a dominant force in Democratic politics?
Well, for one, I would suspect the best results we could hope for might just come from Progressivism either moving away from the conservatives earlier(which would mean significantly lesser support for eugenics, amongst other things, and very little, if any, for racialist eugenics), or not letting them in at all, with the exception of moderates who promise not to rock the boat too much.