We can see that from the Preamble, which reads,It is funny how he can paraphrase the Preamble, and miss the most important word: Posterity.
We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.
That suggests that the Constitution has many purposes: justice, domestic peace, defense against foreign enemies, general welfare, and liberty alike. To be sure, some of them may be seen as aspects of "liberty" in a large sense, such as liberty from foreign oppressors, or even from domestic criminals. But they are not limited to liberty, or even focused primarily on liberty.
The term "We the People" did not refer to American Indians, African slaves, Mexicans, eskimos, or conquistadors. The term "Posterity" did not include future immigrants or foreigners.
Some argue that America is an idea, but what is that idea? Volokh argues that it is not democracy or liberty.