What problems did the US Constitution solve

What problems did the US Constitution solve besides creating the 3 branches of government/Checks and Balances and the Bill of Rights? Written in 1787, ratified in 1788, and in operation since 1789, the United States Constitution is the world’s longest surviving written charter of government. Its first three words – “We The People” – affirm that the government of the United States exists to serve its citizens.