I believe the answer is: <span>a secret intelligence "finding" signed by the president
Even if there is no fact about the finding, all of them had legal ground to act on their own since the finding is acknowledge by the president.
The signed finding indicates that even if their actions were a mistake, the the president would take the responsibility for their action.</span>
People's Party was critical of capitalism and thought that banks and other institutions had the potential to abuse their workers.
They believed that if the government took control over the railroads and banks, it could prevent those institutions from abusing their workers.
OML I actually know a question! they wanted it to make sure that the government did not become too powerful