Final answer:
The primary reason for worsening relations was the weak national government under the Articles of Confederation, which lacked power to enforce laws, collect taxes, or regulate trade, leading to economic troubles and ineffective leadership.
Step-by-step explanation:
The primary reason why the relations between the states and Congress worsened during the years that the Articles of Confederation was the established government was the inability of the national government to effectively lead due to its weak constitution. With no power to enforce its laws, collect taxes, or regulate commerce, the government couldn't manage public finances or secure stable commercial policies. States, sensing the weakness, often disregarded national legislation and interests.
Congress struggled to manage the country's financial obligations, notably being unable to compel states to pay their share of Revolutionary War debt. Additionally, attempts to impose tariffs were often vetoed by the states that had financial interests against such measures. This problem was further exacerbated by events like Shays' Rebellion, which demonstrated the inability of the government to maintain order or protect property.
The inefficacy of the government under the Articles led to poor relations with European powers like Great Britain and Spain, as the United States failed to resolve border issues or secure beneficial trade agreements. The lack of a strong central government meant that foreign countries did not take the United States seriously, which hurt American business interests and led to economic difficulties. Eventually, these issues made it clear that a stronger central government was necessary, paving the way for the development of the U.S. Constitution.