We tried that once. It was called the Articles of Confederation and it failed spectacularly. The 1783 constitution realized the need for a stronger Federal Government for defense and commerce and foreign policy. The genius of the Constitution was that it was a finely balanced solution that created a federal government JUST STRONG ENOUGH to meet those needs and then it narrowly constrained those powers in an enumerated list and then clarified in the 9th and 10th Amendments that any powers not so enumerated remained with the people as expressed by their states. The current mess we are in is because we stopped taking those limits literally. The US Government has allocated powers to itself that the founders never intended and the courts have refused to reign it in. And for all their talk in favour of limited government, the Republicans, once in power, happily take part in the same power feeding frenzy. Once they are safely in the club, they have no problem wielding the same powers. That was I think what Trump was about and why the establishment Repubs fight him to this day.