One at a time, starting with Afghansistan....we need to put a few checks & balances in their governments.
During the writing of the U.S. Constitution, the Founding Fathers were influenced by the writings of Polybius who had described the system of checks and balances in the Roman Republican Constitution. They saw the wisdom of the Roman Republican system and incorporated a system of checks and balances into our own U.S. Constitution.
Polybius, by proxy, was therefore one of our American Founding Fathers in regards to the system of checks and balances.
Polybius and the Founding Fathers: the separation of powers
However, a recurring theme of Polybius' writings, which were a History of Rome written for the benefit of his fellow Greeks, was the theme of the noble and honest character of the Roman Republican citizen during the time in which he wrote. Polybius' time was the era of Rome's Finest Hour, it's life and death struggle with Carthage.
Without that noble character, without that sense of duty to the Republic, without the respect of the rule of law, the citizens of any nation only have a worthless piece of paper for a Constitution. Once the Romans lost that character, they lost their noble Republic regardless of the fact that their Constitution was such a fine document that the Untited States of America chose to found it's own Nation under it's principles 2,000 years later.
I am afraid that no one can put a functioning system of checks and balances into a foreign nation. That is something that only the people can do for themselves. If they have a noble character, they will flourish. If they do not, mere words on a piece of paper will have no effect whatsoever.