Which POD would be needed so that Keynesianism remains as the top economic "school", and is never displaced by so-called Neoliberalism in the 1980s?
This is all the US. You're forgetting what's happening across the pond in Britain with the Thatcherite revolution, though that's monetarism and not voodoo. Unless you have a '50s POD with both parties realizing their policies are unsustainable, the UK postwar consensus will collapse and neoliberalism will be birthed there.
You can do both with a POD in '76...That's a fair enough point, so perhaps a better question is, is there any way to prevent neoliberalism from becoming a pseudo-religious orthodoxy in the United States and keep the pro-freemarket conservatives in this country, well, sane? As in more like the post-Thatcher conservatives in Britain who seem to accept that public institutions like the NHS should continue to exist instead of like American tea party "conservatives" who seem to think all public institutions should be abolished?
Maybe a better way of putting that is, is it possible to have a *neoliberal right in the US that believes its task is to manage the welfare state more economically, rather than seeking to abolish it?
You can do both with a POD in '76...
Ford or Reagan wins in '76.
Falklands War happened in '76 or '77 as it almost did. Or Heath wins in '74.
The only requirement is to prevent the Carter depression. Arguably, the precipitating element here was the oil shortage. Therefore: James Earl Carter declares his support for Iranian revolutionaries against Shah Rezi Palavah. Congress fumes, but no hostages are taken. Moderate 'Leftists' remain in control of Iran, but neutral in the Cold War and anxious to stay friendly to both sides. Iran steps up oil production to raise capital. With no Energy Crisis and no depression, incumbent Carter narrowly wins re-election in spite of the Panama Canal Treaty. By 1984, after a period of severe inflation, the economy is thriving and the Goldwater/Reagan 'rednecks' are all but forgotten.
A few years later, Soviet Premier Gorbachev is ousted and President Mondale claims credit for victory in the 'Cold War'.