After two total and all out wars the countries had realized that the absolute chaos of a war would bring the world to collapse if aggressive policies were still relied on.
Explanation:
The two world wars that happened in a span of 20 years had ruined the economy of the European nations and brought the countries to a virtual stand still with the loss of millions of young men.
The war brought destruction to even the winners enough to not justify all out conflicts anymore.
The presence of nuclear weapons by the end also brought the reality of a nuclear war to the fore as there would always be a possibility of nuclear attacks if wars escalated.
The conflict would prove to be too costly if it ever happens.
In exchange for the food and clothing offered by Spanish missions, many different tribes agreed to show the settlers how to properly plant and cultivate crops, which was difficult for many settlers.
Congressional legalization of Hoover's executive order that had blocked immigration. Direct loans to state governments for spending on relief for the unemployed. More aid to Federal Land Banks. Creating a Public Works Administration that would both better coordinate Federal public works and expand them.