There are two reasons that interest rates represents a growing slice of the federal budget: (1) As long as the federal government spends more than it takes in, it'll be borrowing more each year; and (2) the interest rates the U.S. Treasury pays on its borrowing are really low now, but they won't stay low forever.
There are two reasons that interest rates represents a growing slice of the federal budget: (1) As long as the federal government spends more than it takes in, it'll be borrowing more each year; and (2) the interest rates the U.S. Treasury pays on its borrowing are really low now, but they won't stay low forever.