Almost Socialism

I'm a big fan of Daniel J. Mitchell's blog where he shared the following tweet:

“Real Socialism” has never been tried in the same way that “Real Capitalism” has never been tried.

The difference is ‘almost Socialism’ resulted in the impoverishment & death of hundreds of millions of people.

While ‘Almost Capitalism’ has lifted billions from absolute poverty.

— Mark (@markantro) January 23, 2018

Advocates for socialism often claim that it has failed so far because "real socialism" has never been tried. With so many examples of failed "almost socialism," is it really a good idea to abandon capitalism or strive for more of it?