Why was the resolution of the federal government’s fiscal problems so critical to the success of the new nation?

Because the federal government was bankrupt, and without solving its fiscal problems, it could not raise an army in case of invasion from foreign powers, like Britain or Spain.

This is why the US constitution gave the federal government the faculty of raising federal taxes, in order to raise the necessary amount of money to protect the union.

the articles of confederation only set up the continental congress at the federal level. there were no executive or judicial branches except within the states. the states were allowed to keep every right that was not specifically given to congress. the bonding of the states was through a 'firm league of friendship' that best served as a defense agreement against invasion. states were not allowed to use taxes as a way to discourage treaties, and states were extremely limited in their dealings with foreign nations.

not many historians today talk about the strengths of the articles of confederation, likely because of how unpopular the document quickly became. the articles did set the legislative body, congress, as the highest power in the nation because of the fear of monarchy. congress had the sole power to declare war, assign treaties, entertain foreign relations, and operate post offices. disputes between states and territorial issues were to be brought to congress. the document also stipulated that canada was allowed to enter the union if they desired.

there were more weaknesses than strengths under the articles of confederation. the lack of power given to the continental congress strangled the federal government. the articles gave congress the power to pass laws but no power to enforce those laws. if a state did not support a federal law, that state could simply ignore it. congress had no power to levy taxes or regulate trade. without a federal court system or executive leader, there would be no way to enforce these laws, either. amending the articles of confederation would also require a unanimous decision, which would be extremely difficult.