Contextualization means describing a broader historical process connected to the prompt - either the lead-up before the time period, or how its themes continued beyond it. Both directions count fully.
"In the decades following the Revolution, slavery shaped nearly every dimension of American life..."
This doesn't earn the point - "in the decades following the Revolution" is a passing reference to the timeframe, not a description of a broader historical process. Adding 2-3 sentences on how Revolutionary-era ideals of liberty conflicted with the continued expansion of slavery would earn it.
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