Why did de Crevecoeur find it difficult to define what constituted an "American?"

What clause(s) expanded the power of the executive branch, especially relating to foreign policy?

What does munich’s refer to in the 13 days?

The 20th amendment, also called the lame duck amendment, decreased the amount of time between the presidential election and the inaugration of the new president. what are the advancements that allowed for this amendment?