"Then" is used in an "if-then" scenario, to dictate chronological order. In other words, "If you jump off, then you will fall," or "he was attacked and then retreated."
"Than" is used for comparisons. In other words, "The egg was bigger than the pea," or "I'm stronger than you."
Topic or Theme? The Theme of the poem is the relationship between light and darkness.
Japanese Americans were AMERICANS. They were citizens of this country. We presume innocence until proven guilty here. They were not tried and found guilty. They were simply rounded up on the basis of their ethnicity.
German Americans were not interred, but they were of European descent not Asian. To imprison the Asians but not the Europeans who could possibly be friendly to the enemy was racist.
Japanese Americans were trusted to serve in the US armed forces as did German Americans. Many served honorably fighting against possible relatives and family friends. If they could not be trusted, they shouldn't have been allowed to defend the nation in the armed forces.
