Final answer:
Kings and tyrants in the poem symbolize oppressive and authoritarian regimes, contrasting the ideal of America with the reality for many.
Step-by-step explanation:
In the poem Let America Be America Again, the mention of kings and tyrants in line 8 symbolizes the oppressive forces and authoritarian regimes that have historically curtailed freedom and justice. The reference to these figures is used to contrast the vision of America as a land of liberty with the reality that, for many, the promise of America remains unfulfilled. The symbolism of kings and tyrants speaks to the broader theme of the poem, which is a critique of the American dream and a call for a return to the foundational ideals of equality and liberty.