Final answer:
When a part of a legislative code is deemed unconstitutional, it becomes invalid due to the precedent set by the Supremacy Clause, stating the Constitution overrules conflicting laws.
Step-by-step explanation:
When a section, subsection, sentence, clause, or phrase of a legislative code is found to be unconstitutional, the decision typically renders the specific part invalid. This principle aligns with the doctrine established by the Supremacy Clause, which states that the Constitution is the highest law of the land, overriding any conflicting state law or legislative act.
In historical cases, such as with the establishment of a national bank, the Necessary and Proper Clause indicated Congress has certain implied powers to enact laws essential for executing its enumerated powers.
Furthermore, the landmark decision of 4 votes for Madison established the clear precedence that when legislation conflicts with the Constitution, it is considered void, underscoring the Constitution's role as the paramount law of the nation.