Final answer:
Frank Palko thought the Fifth Amendment's double jeopardy clause applied to his case because he faced a second prosecution for the same crime after being acquitted.
Step-by-step explanation:
Frank Palko believed that the Fifth Amendment ban on double jeopardy applied to his case because he was being tried twice for the same crime. The Fifth Amendment protects individuals against double jeopardy, which means a person cannot be prosecuted again for the same crime if they have already been acquitted. However, there are nuances to this protection. The ban on double jeopardy prevents a second prosecution only at the same level of government (federal or state) as the first.
In Palko's situation, he contended that his second conviction by the state of Connecticut violated the Fifth Amendment's double jeopardy clause. His case ultimately made its way to the Supreme Court, which had to determine whether the Fifth Amendment's protection against double jeopardy was a fundamental right that states were required to observe under the Fourteenth Amendment's due process clause.