Your credit rating determines the cost of borrowing money - the AAA status is essential if you want to borrow money (i.e. issue bonds to) some of the biggest, m

Your credit rating determines the cost of borrowing money - the AAA status is essential if you want to borrow money (i.e. issue bonds to) some of the biggest, most risk-averse funds in the world. If the US loses its AAA rating then you cannot sell bonds so easily and therefore it becomes harder to raise money or balance the books without politically-unpopular tax raises or service cuts.