Depends how big a deficit you're running each year. But 'catch up' is a really vague term. As long as you can keep borrowing at low interest rates there's no pr

Depends how big a deficit you're running each year. But 'catch up' is a really vague term. As long as you can keep borrowing at low interest rates there's no problem, you can just borrow more to pay the interest, but eventually people will start to doubt your ability to pay it all back (yes this is irrelevant if a country exists forever, but infinity is weird like that).