First off, just to be clear, SS is only 'insolvent' (according to your definition) in the worst-case-scenario (that's the one where there's an increase in lifespan equal to the one for the past 40 years
(most doctors doubt there will be), pretty much everyone retires as soon as they're able (many won't), that the economy expands at the lowest estimated rate based on the past 40 years (the average rate from the past 40 years is quite a bit higher) and so on.) Its entirely possible that SS is entirely solvent now - many predictions say that it is. One good flu season in the next 40 years and it will be.
Secondly, SS doesn't HAVE any debts. What it has is projected expenses. There's a big difference there. A debt is a specific amount that you WILL have to pay. A projected expense is an amount that you may have to pay, depending on a whole lot of other things.
Thirdly, even if worst case scenarios come to pass, SS will at that point have a rather minor debt. That will continue for less than 15 years (even according to worst case scenario) before it moves back into the black, at which point it'll be quite able to pay off its debt. So your claim that its insolvent, according to your definition, requires looking at a very specific time period and not the full long-term future. What you're saying is that if you ever go into debt, even if you know you'll be able to pay it off later, you're insolvent.