Yep. Eventually your lenders want to be repaid. This is why most sovereign debt is rolled over. The EU has put Greece in a situation where it can't roll over its debts and must pay them as they come due. Almost no nation can do this for all of its debt. Think of it like this, you can payoff your home mortgage over thirty years, if the bank suddenly accelerates it and demands all of the money tomorrow that isn't going to be doable unless you can find another lender. Unfortunately, the sovereign debt markets tend to dislike long maturity bonds. This means the only loans many nations can get need to be repaid in five or ten years. In normal circumstances a nation can roll their debt over.
^ all true...
How many nations could? Germany *might*, given their huge hard currency reserves, plus their gold and other physical assets. (Many people don't know this, but after the United States, Germany holds the world's largest gold reserves)
China probably could, given the massive foreign currency they hold.
The US of course could, given that the US Dollar is the world's reserve currency, we could print enough to pay it all off tomorrow, abit at the cost of inflation, but we could.
Who else? Honestly, I think that might be it.