Final answer:
A central idea in the preamble is the provision for the common defense, paired with establishing justice, tranquillity, welfare, and securing liberty as key objectives of the Constitution to serve the people's well-being.
Step-by-step explanation:
One central idea established in Gouverneur Morris's preamble to the United States Constitution is the concept of providing for the common defense. This highlights the need for a cohesive national defense to protect the new nation. Furthermore, the preamble outlines other key objectives such as forming a more perfect union, establishing justice, ensuring domestic tranquility, promoting the general welfare, and securing the blessings of liberty. These aims collectively underscore the intent of the Constitution to create a government that is powered by the people and serves to protect and enhance their collective well-being and freedom.