Verdict: Opinion. Commentary cites multiple failed socialist experiments, but that evidence does not establish a 100% failure rate across every instance. The central reason is that “socialism” has competing definitions, making a universal failure judgment dependent on how the term and success are defined.
Socialism fails 100% of the time.
The Claim
Socialism fails 100% of the time.

You Can't Argue against Socialism's 100 Percent Record of Failure
Source: fee.org
What the Evidence Shows
What is established
One commentary article asserts failure across several named socialist experiments.
Another article claims that more than two dozen attempts failed, but its cited scope does not cover every instance of socialism.
An opposing commentary asserts that socialist societies produced measurable gains, which challenges an unqualified universal-failure assertion.
Context and caveats
The claim omits disagreement over what counts as socialism and disagreement over which outcomes should determine whether a society succeeded or failed.
The approved evidence consists of commentary and does not provide a comprehensive, independently verified dataset covering every instance of socialism.
The approved evidence does not define a single consistent standard for “socialism,” “failure,” or “success.”