Answer:
The major innovations of the 1787 U.S. Constitution were:
1. A federal system of government that balanced state and national power. The Constitution created a stronger central government than under the Articles of Confederation, but it also preserved significant powers for the states. This federal system avoids both extreme centralized and decentralized governments.
2. The system of separation of powers and checks and balances. The Constitution separated the government into three co-equal branches - legislative, executive and judicial - and gave each branch the ability to check the powers of the others. This prevents any one branch from becoming dominant.
3. An independent judiciary with the power of judicial review. The Constitution established the Supreme Court as the final arbiter of constitutional disputes. This allows the judiciary to invalidate laws that violate the Constitution, ensuring it is upheld.
Some major flaws of the Constitution, past and present:
1. It perpetuated the institution of slavery by compromising with slaveholding states. The original Constitution contained provisions protecting the slave trade and failed to explicitly abolish slavery.
2. It failed to explicitly guarantee many individual rights and civil liberties. This led to the addition of the Bill of Rights soon after to protect freedoms like speech, religion and due process.
3. It established an electoral college system for electing the president that does not always match the popular vote. This is seen by some as undemocratic and outdated.
4. It has not kept up with changing times and societal values. Critics argue key parts of the Constitution have required frequent amendments to adequately protect marginalized groups and reflect modern principles of equality and inclusion.
Hope this overview of major innovations and flaws of the U.S. Constitution is helpful! Please let me know if you have any follow-up questions or need any part clarified further. I'm happy to discuss any aspect of this topic.