Borrowing billions/trillions to spend on your economy will greatly increase your debt load and also thus your interest payable vis-a-vis the budget.
Why would you want to increase that interest payment through higher interest rates when it's already increasing through greater amounts of debt?
And what would happen if that interest rate skyrocketed through some device of its own?
TSHTF
I was saying that if Germany is having trouble selling their bonds, we might have to offer higher returns for investors on our bonds if we plan on spending $1 trillion on a stimulus package.