[ProgressingAmerica]

Problem is, it isn't simple. An ideology such as progressivism, which morphs at least three times by definition cannot be simple.

However, I can make it quite simple in the following regard:

America's first progressive president appeared in 1900. That is not the same year America's first communist president appeared.

[ProgressingAmerica]

Slip of the keyboard there. Meant to type 1901. The first progressive president did not serve two full terms.

[reasonisfaith]

To understand a concept is to be able to articulate it.

If you understand how progressivism is allegedly different from communism, you will be able to state it in one sentence.