Question

The most significant new deal reform enacted in 1935 was the

Answer 1

Social Security Act.

Social Security is still with us today as a part of the structure of American society.  Some other New Deal programs have had long-term existence within government agencies and programs too.  For instance, the Farm Security Agency, which existed till 2006, was an heir of the Farm Security Administration created in 1937.  Some of the programs of the FSA now are handled by USDA Rural Development.  But that's an example of something dealing with a portion of the American populace.  Social Security is a program that encompasses all Americans and is a backbone of social welfare policy.