@Yellowdog . China, and Russia, attempt to curtail religion. But that’s just because religion was invented to control/manipulate people. Hard to control and manipulate people, who are already being controlled by religion…
North Korea’s leader is a “living god,” to it’s citizens. So that is a religious country.
In any case, all three examples you provided were not examples of a government with atheistic leadership, or government officials.
And your mentioning of the US’s founding documents leaves out the most relevant part to this discussion. That is, that our founding fathers made it crystal clear, that there should be a separation of religion and state. Other than quoting some of our founding father’s opinions on religion, it is far easier to conclude that the importance they placed on separating religion, from the government indicated that they were fully aware that religion should be excluded from the members of society’s most important roles…
More to the point of the question, there would still be greed, and emotion, in an atheist led nation. So, it wouldn’t magically be a completely peaceful, and unbiased place.
I do find it would likely be a vastly improved society, in almost every possible way. Admittedly, there would probably be some draw backs, although I can’t think of any…