The United States even from its creation has always been divided in terms of ideology. There were arguments about states rights vs. the national government back even during the founding of the country. Even today, it appears we have become completely polarized and divided on different sides.
I do think the thing that unites the United States is not economics but a belief in an ideology surrounding core principles. Some of these core principles such as a right to free speech are enshrined in the constitution. The Declaration of Independence put forward the the idea that all people are equal. While Americans might argue about the direction the country takes, it are these beliefs and practices that unite Americans in a common union with each other.
What ideology is that? The only thing the US seems to have to bring people together is the possibility of getting rich here.
Am I missing something?
Agree with rockjon. Federalism, as advocated by James Madison and Alexander Hamilton, was a way to protect our core values against an over-reaching federal government (i.e., a monarchy or dictatorship). Our core values were those listed in our Bill of Rights. You can find the full list here https://nccs.net/online-resources/us-constitution/amendments-to-the-us-constitution/the-bill-of-rights-amendments-1-10
Do you believe those are the same values are guiding America today? Sure I can believe it was back then for at least a small minority of enlightened Americans.
Unfortunately, I agree with you. These should be the values that are guiding us today, but many people have abandoned them. Yet, I don't think you have to be a Strict Constructionist to appreciate their merit.