Checks and balances
supreme court is granted power to overturn congressional laws that violate constitution. the courts however should exercise judicial constrain while doing that, to ensure the do not injure the principle of separation of power. usually they all restrain themselves to comparing whether the new law contradict the establishment clauses which would require a referendum, or the wording and legal process was followed. This ensures congress is checked.
Letters would be an example of a primary source
Mexican immigrants wanted to escape poverty, war, turmoil, and even persecution for certain groups
