<p>In the past, the small nation [had been committed to] self-managed socialism, a system [under which] the workers, [rather than] the state, [owns] most enterprises.</p>
<p>Why is "had been committed to" correct? I thought you only used past perfect tense to describe one event happening before another past event. Shouldn't it have been, "In the past, the small nation WAS..."?</p>
<p>The past perfect tense use implies that sometime in the past the nation was committed to self-managed socialism, that it continued with this commitment to another time also in the past and that today it is not longer committed to this form of government. The prepositional phrase “in the past” is consistent with this interpretation. The explicit event that you are looking for is in fact implicit – or perhaps it is identified in a “previous” sentence. In any case the “rule” that you’re expecting is not as explicit as you imagine.</p>
<p>The error of course is of the subject - verb agreement variety. It’s in the clause “the workers etc.”. The noun “workers” (plural) requires “own” (and not owns).</p>