It is wholly inadequate to the government of any other. Without inward morality, constitutional government is totally non-existent. The rule of constitutional law over the affairs of men is absolutely dependent upon the rule of divine law within men's hearts. The breakdown of the latter quickly leads to the breakdown of the former. That is where the United States is now.
Divine law has little, if any, influence over our society today.
The two are inseparable twins. To find one is to find each. Look at the way government approaches problem-solving today. The answers recommended by both major parties are tolerance of evil and ever-burgeoning government bureaucracies. The two parties argue only about how much to increase the stranglehold of government authority.