What is the right fiscal policy?

What is the right fiscal policy? People differently placed on the politico-economic spectrum will give you radically different answers.
At one extreme, you have the hairshirt fiscal purists who think government borrowing is always wrong and who won’t be happy until all that debt has been repaid. At the other, you have the Keynesian fundamentalists who believe that the Government can carry on borrowing until the cows come home.
A lifetime in economics has taught me that the right fiscal policy changes with circumstances. And ours have been through a revolution.