What can the US learn from civilizations such as the British Empire, Roman Empire, Mongol Empire, etc, to prevent it from declining in the same way?

(My answer on Quora)

A tremendous amount can be learnt from each. They all have a fascinating history. What follows is an outline of key takeaways.

From the British Empire

• Use trade to solidify your Empire (Helped Britain in the Napoleonic Wars and the World Wars of the 20th century)
• Export Cultural norms (such as Cricket) even if the locals eventually learn to play the game better than you
• Move your key colonies to self-determination in a progressive manner
• Prioritize education
• Create a necessary civil service infrastructure in your Empire to reduce the Cost of an external administration footprint on the mother country
• Be mindful of wasting resources on defending remote parts of the Empire
• Gunboat diplomacy can go a long way
• Divide and conquer will take you so far but eventually there will be a backlash

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British Empire Map Source: British Empire | System | Bas Feijen

From the Roman Empire

• Build Transportation infrastructure to facilitate communication within your Empire
• A solid legal system can go far
• Never allow Local Administrators to become too powerful in their own right
• Make sure your elite doesn’t become decadent
• Limit the power of the Army in key areas of decision making
• Don’t outsource areas of defense to groups that are essentially hostile to you
• Make sure you have an effective system to get rid of incompetent rulers
• You can only keep bribing your enemies for so long
• Be careful of economic rot and the devaluation of your currency

Roman Empire Source: Roman Empire in 117 CE

From the Mongol Empire

• If you are going to control a vast land territory make sure that you have a system of administration that can assist in the administration of these gains
• If you offer nothing of long lasting cultural value to the territories you conquer then their culture will become yours
• You will not defeat every opponent through fear and brutality
• Be mindful of sibling infighting when dividing up your Empire (power structure)
• Your opponents will eventually learn to use your strengths against you

Mongol Empire Source: How the borders of the Mongol Empire changed in the Middle Ages - Medievalists.net

From All Three - Empires will eventually fall. Make sure you leave a legacy that is worth preserving.