Answer:
The six big ideas are:
Limited government. - is still relevant because a too powerful government can be a threat to the people, as it has been seen in history many times.
Republicanism - is still relevant because the United States is a republic, where government is a public matter, and is obliged to respond to the people. The people also have the right to change and remove the government if they feel it is not working for the common benefit.
Checks and balances - is still relevant. The three branches of government: the executive (president), legislative (congress), and judicial (the courts including the Supreme Court) all have checks and balances. Each branch checks the power of the other two, and this prevents any of the three from becoming too powerful.
Federalism - The U.S. is a federal republic, therefore, it is still relevant. This is why the federal government only has those powers explicetly given to it by the constitution, while everything else is left up to the states.
Separation of powers - Is still relevant and related to the principle of checks and balances. The U.S. is a republic where government has three separated powers or branches, the executive, the legislative, and the judiciary.
Popular sovereignty - is still relevant. In a republic, the people are the ones who really control the government, who elect the government, and who can remove and change the government. This is popular sovereignty.
