I'm a broken record on this-the best way to wank the Democratic Party is for Chiang Kai-Shek win the Chinese Civil War. That very likely butterflies to no Korean War. RAC victory in Chinese Civil War + No Korean War means no or much milder Red Scare. At that point, in 1952, there are several directions to go. Eisenhower is very likely still a nominee for president (the momentum for him is simply too strong for me to see another outcome). His party affiliation under this scenario is up in the air for me, but really, you can still wank the Democratic Party no matter which side Eisenhower joins. Even as a Republican in OTL, Eisenhower worked better with Sam Rayburn and Lyndon Johnson than he did with the Republican leadership in Congress, and did little to campaign for congressional Republicans. In fact, given how common voter fatigue gets in America, if you want a Democratic wank, then it would probably be better if Eisenhower remains a Republican so that the country has a break from 20 years of Democratic presidents.
Following Eisenhower is where things would get murky, and it also depends on whether one would rather have a Democratic wank or a liberal wank. If it's a Democrat wank, then the most obvious POD is to have the Dixiecrats remain Democrat or keep their vote up for grabs between the two parties. I really don't like that particular scenario, so I haven't put much thought into the details, but that's my first thought in terms of wanking the Democrats.
I have given a lot of thought to a liberal wank, but the scenarios are much more complicated, and many of them have to do with events that took place in Eisenhower's term. How does an RAC victory in Chinese Civil War effect events in Vietnam and Cuba? There's a much straighter line to the Korean War and Chinese Civil War than there is to the Vietnam War. If the country is not in a panic over "losing" China, does Ike go along with the 1956 Geneva Accords, and just simply ignore Vietnam altogether? (in retrospect, the better decision). If he does go this route, the Democrats can still pull together a win in 1960 (this is another potential butterfly), then we can still have a scenario of a New Frontier/Great Society program getting passed without the burden of the Vietnam War lurking over the country. This is where things start to get vastly more complicated than even the craziest fan theories about Back to the Future. There are still several unresolved questions, such as:
-with softer or no Red Scare, does Eisenhower still pick Nixon as running mate in 1952? And who runs in 1960 for the Republicans? This is a big question regarding either a Democrat or liberal wank.
-how does Civil Rights movement play out? We often mingle the anti-war protests of the 60s with the civil rights protests, but the heated Civil Rights struggle had been going on since the 1950s, before most people had heard of Vietnam, so butterflying away the Vietnam War doesn't do much to effect this issue. In OTL, I think the problem for the civil rights movement was when there was opposition in the North to attempts to address de facto segregation. De facto segregation has its roots in the 1920s and the way the U.S. ended up designing its transit and mass highway system. I've seen a few timelines on this board about that, so maybe someone more familiar with them than I am can post some links. But if you can reduce Northern opposition to Civil Rights, then you have the potential for a strong wank.
-the economy of the 1970s is still a problem. You have 2 issues here-the countries of Europe and Asia are by this time still going to have recovered from WWII, and the lack of foreign competition that America enjoyed for 20 years will be ending, no matter who is running show in the U.S. The other pressing issue is America's dependence on foreign oil. The Arab Oil Embargo of 1973 and the Iranian Revolution of 1979 are still huge potential shocks for any administration, Democrat or Republican, in the 1970s. Please don't ask me to address this now because I foresee a huge headache in any topic that has the words "Mideast" and "oil" in it.
-and actually, my original POD-an RAC victory in the Chinese Civil War, may itself be ASB. I think it's doable, but you would need an America that was considerably more prepared for WWII than in OTL. Not impossible, but difficult. In the 1930s, no one, even the Republicans, were calling for massive military mobilization. Prior to the Cold War, the U.S. never maintained a large peacetime military force. While I don't think ASB is required to have a better mobilized U.S. from 1939-1941, it's not a simple solution. But I think that's where I'd begin.