Right, I'd forgotten about McKinley! But didn't McKinley pass the tariff act to protect domestic manufacturers? The "us vs them" in that situation was also pretty clear.
McKinley got the Tariff Act through in 1890 when he was in the House, but another tariff law replaced it in 1894. McKinley was elected president in 1896.
Which still gave him a common enemy - the Great Depression.
Also, neither presidents were against corporate america! TR might've presided over the passing of the Sherman Anti-Trust Act, but he made sure that the focus was about the "abuse of monopoly power", not the monopoly itself!
FDR didn't blame corporate power and restored faith into the banks to start businesses running again.
The Sherman Anti-trust Act was passed in 1890. TR became president in 1901. In its first years the Sherman AT Act was used to break up trade unions. Roosevelt got things going with breaking up monopolies, but Taft did more than Roosevelt.
Sometimes monopolies are unavoidable. We had one phone company for decades because technologically it was pretty much impossible to get competition to your home or business. There were a lot of other places where monopolies had to or have to exist.
By 1900 the bulk of the US population was aligned against the abuses of the monopolies and TR was the leader who championed breaking them up. The monopolies were the common enemy. Read some of the classic American books of the 1890s, many are about abuses to workers that were happening that are very similar to China in the last couple of decades.
And for FDR have you ever heard any of his speeches where he goes after corporations? One I recall he said the corporate leaders hate him and he's proud of it. There were a number of banking reforms passed in the 30s that limited the size of banks and what they could do.
And we have a couple of enemies or potential enemies today. One is a potential depression and the other is COVID-19. If COVID-19 cases explode around the country in the next month or two (I think it's inevitable with the Republican controlled areas almost encouraging people to congregate), the Republicans could become the common enemy.
As for being anti-corporation, that's not a good idea. Corporations as a concept are neutral. They are a way to organize a business entity and can be a good thing if used properly. The problem is that bad actors have abused the corporation laws and practices to do harm to others. That definitely needs to be reigned in.
I am in favor of corporate reform and prosecuting the people who have broken the law and passing new laws to close loopholes crooks have used to legally steal money or get away with doing harm. But I am not in favor of doing away with corporations. That would be way too heavy a lift for the United States to attempt and it would almost certainly fail and fail spectacularly.
When trying to change the system you make much better progress when you cut with the grain rather than completely against it. If you only try to change a few strategic memes rather than change everything, you stand a decent chance of success. If you try to change too much too quickly, there will be a massive backlash that will throw you out of power.
The ACA was a very watered down medical reform, but the Republicans successfully sold it as a massive overhaul of the medical system that was going to destroy everything and they succeeded in crippling it in many ways to a point where its effect has been very minimal.
Right now, with Biden as the nominee, I'm not so sure. Also, if the economy recovers from COVID-19 for the summer, the republicans will have a wind in their sail (Since Trump will claim to have "beaten the virus", and could possibly win, but only just in time to experience the second outbreak wave when the flu season returns and again mis-handle the federal response to a global crisis. Some things I just don't want to take a wait-and-see position.
If the virus goes away this summer, the Republicans will be in a strong position. But it will be blind luck rather than planning. The best crisis managers in all this are looking months ahead while Trump is looking a day ahead at most.
Everywhere in the world where people have been free to associate freely until the virus gets dug in have had bad outbreaks of the virus. That's happening right now in many red states. The Democratic governor of Kansas tried to put in a stay at home order, but the Republican legislature overrode her. The governor of Arkansas put out an executive order banning local leaders from instituting stay at home orders.
This is almost certainly going to lead to big outbreaks in many of these red states. We will see New York turn the corner soon, and the west coast is already got things slowed down. But it's going to spread to the areas which were slow to issue stay at home orders and it will likely be a rough summer in some parts of the US.
If what I think will happen does come to pass we will have many shining examples of how to do it right and how to right and how to do it wrong by the end of the summer.
