One would think that the amount of debt one has in ratio to the GDP might hint about the economic stability of the currency.  At some theorhetical point interest payments will exceed the governments ability to collect revenues.  In that case, why bother investing into the economy it if you will not get anything in return-or even junk for return.

Under a weak ago Argentina reached the poit where it had asked the IMF for an early release from a <a href="https://www.cnbc.com/2018/08/30/argentina-crisis-peso-crashes-to-record-low-amid-imf-plea.html">50B billion dollar bond</a>.  The Argentina inflation rate was close to 30% until that point-then the value of their peso dropped to 45% against the dollar, and interest rates are as high as 60%. Good chance they, Latin America's third largest economy, will become a Venezuela like state.
  The Argentina debt to GDP ratio was an irresponsible 57%.

Turkey us undergoing similar problems because of a trade Issue with President Trump.  The <a href="https://www.yahoo.com/news/turkey-inflation-surges-15-high-august-101137398.html">Turkish Lira</a> has dropped 25% against the USD, and consumer prices are up 17.9% over the last year.    It is still too early to tell the long term prognosis for turkey.  Not all of this can be blamed upon Trump's trade war.  The Turkish central banked <a href="https://tradingeconomics.com/turkey/interest-rate">raised interest rates 18% in july</a>.   
Luckily their debt to gdp rate is about <a href="https://tradingeconomics.com/turkey/government-debt-to-gdp">28%</a> .  

Hyperinflation is well know in venezuela, and the country is struggling to pay its debt obligations.  Their debt to GDP ratio is a <a href="https://tradingeconomics.com/venezuela/government-debt-to-gdp">mere 23%</a>-the best in 10 years.  But how accurate is such a measure when their inflation rate is <a href="https://tradingeconomics.com/venezuela/inflation-cpi">82766%</a>


 So even a debt to gdp rate of 23% can signify a very troubled nation if it cannot keep inflation under control.  
But then you look at some countries.  Japan has a debt to gdp ratio of a <a href="https://tradingeconomics.com/country-list/government-debt-to-gdp">whopping 255%</a>, greece is 178%, Lebanon 149%, Italy 131.8%, Portugal 125.7%, and in tenth place is the United states at 105%, about 25th place is the United kingdom at 85.3%.

So a high debt to GDP ratio does not spell the end of the world.   Japan seems to have a scheme where it sells its own notes to its own bank of japan at low interest rates, and it is said that many of the loans are forgiven.  The IMF wants japan to develop long term plans to deal with its debt problems, but nontheless japan has decided instead to delay austerity measures in <a href="https://www.reuters.com/article/us-japan-economy-fiscal/japan-to-backtrack-on-budget-target-social-welfare-reform-as-tax-hike-looms-idUSKCN1IO08E">favor of taxes and social welfare</a> while also claiming it can reduce the debt to gdp to 180% by 2021.  Probably that means printing more money, which means more inflation which means it will be that much more expensive to provide social services.

  Greece could of have its own Venezuela type scenerio-except they had the benefit of a stable Euro-but was bailed out 3 times by the European union and forced  to engage in austerity measures.  Unemployment was at 27% and the government ran at a deficit, <a href="https://www.theguardian.com/world/2018/aug/20/greece-emerges-from-eurozone-bailout-after-years-of-austerity">now</a> the unemployment rate is under 20% and is running a surplus.  However, not even before the bailout period ended, the Greek prime minister vowed to engage in more social spending.  Meanwhile, the governor of the central bank warned that Greek was dependent of the economy of Italy and Turkey.  Oops.  The mess in greece began when the debt to GDP rate <a href="https://www.haaretz.com/israel-news/.premium-jordan-and-lebanon-are-going-broke-and-israel-should-worry-1.5991336">was 130%</a>.  

Lebanon this order ordered all ministries to cut <a href="https://blog.staffordglobal.org/news/austerity-in-lebanon">20% off of their budget</a> for austerity reasons.  There have also been <a href="https://www.haaretz.com/israel-news/.premium-jordan-and-lebanon-are-going-broke-and-israel-should-worry-1.5991336">increased taxes in 2017</a> and the country has been taking on 1.5 million Syrian immigrants-about a 4rth of Lebanon's population.  

Italy has been under European Union austerity measures since 2013.  However, studies are finding  <a href="https://www.washingtonpost.com/news/monkey-cage/wp/2018/07/25/italians-are-tired-of-living-under-austerity-that-could-be-a-big-problem-for-europe/?utm_term=.6e9bb3ca562e">the italian people</a> do not like austerity and the government has failed to produce economic growth.  One has to wonder if they will have their own "Brexit", or simple spite the Eu and descend further into the abyss.


  the new York times seems to be applauding Portugal's refusal to implement austerity measures, and the NY Slimes claims spending is what accelerated the economy.  Well not so fast, in <a href="https://www.nytimes.com/2018/07/22/business/portugal-economy-austerity.html">the same Slimes article</a> it was private investments that improved the economy including investments in automating the olive oil industry, tourism,  as well as the expansion  of Google and other private party investments.  It is pretty sad for a country to essential say one agricultural produce made up 40% of their export activity, and that it is pretty much all done by robots.  Unions want more anti-austerity measures, but the politicians are at least brightest than the NY times in telling them no.

Anyways not far behind is the big bad United states at 105%.     And that is just the national debt.  When we add on state debts, that is <a href="https://www.usgovernmentspending.com/compare_state_spending_2017bH0a">another 1175 Billion</a>.  And when we add on local debts, that is another 1800 Billion.  Presently the US national debt is about 21460 trillion.  So a core comprehensive debt to gdp ratio is about 119%.And one by one governments are increasingly  failing,and the state of Illinois (state of Obama) <a href="https://money.cnn.com/2017/06/29/investing/illinois-budget-crisis-downgrade/index.html">bonds were once ranked junk</a>, and <a href="https://www.washingtonpost.com/opinions/connecticut-is-drowning-in-debt-should-its-neighbors-have-to-pay/2018/07/23/eff14b6a-83be-11e8-8589-5bb6b89e3772_story.html?noredirect=on&utm_term=.b74c813ab14a">Connecticut may soon follow</a>.  And many cities, most notably <a href="https://www.sacbee.com/opinion/editorials/article199693069.html">in california</a>, are in trouble too.    But I suppose considering state and local debts are not done in the analysis of other nations.   But nonetheless as more and more local governments fail, it negatively affects the psychology of those who might otherwise invest in state or municipal bonds. Whose next?
  The United states represents about 25% of the word's GDP.  The interest that we pay on our debt represents about .38% of the world's gdp.  
 Nationally the approach to the debt is on banking on future economic growth.  keeping loans low so businesses can borrow start up cash-keynesian based economics that hurts fiscally minded people-especially poorer ones.   Issuing tax cuts on the premise that businesses will create additional revenue through more economic activity-and engaged in more spending. A more dangerous approach is the idea of spending your way out of debt or another form of keynesian economics that ravaged japan, and sadly the 1.8 trillion dollar omnibus package approved this year was a fiasco.  The United states also haven't engaged in any for of austerity measures to speak of, although they have engaged in printing new money-or quantitative easing-which risks inflation.   What the United states as a country doesn't have is a problem in : paying back its current obligations, borrowing new money, inflation, and dangerous interest rates.  All a matter of time.  There are at least 9 other countries presently more vulnerable than the United states, many of which had to be bailed out and adopt austerity measures to avoid financial ruin.  And as big as the United states is, we will be too big to be bailed out.  States and localities do not have the ability to engage in quantitative easing, and the federal courts can't be used to compel the state courts to pay off their bond obligations unless there is some waiver. 
  The rates to buy US bonds at the <a href="https://www.treasury.gov/resource-center/data-chart-center/interest-rates/Pages/TextView.aspx?data=yield">treasury department</a> fluctuate between 2-3%.  so of the 21460 Billion, at today's rates (it's technically not that simple as there are still 30 year bonds from the 90s paying much better rates)  one could estimate that the interest paid each year is between 429 Billion and 643 Billion.  Which is interesting, the <a href="http://www.usdebtclock.org/">debt clock counter</a> suggest that the annual amount being paid is about 312 Billion.  In another words, it is more expensive now to borrow money than say over the last 10 years or so.

At an eye level look, there doesn't appear to be a easily identifiable stochastic process for the US debt to gdp ratio as <a href="https://www.thebalance.com/national-debt-by-year-compared-to-gdp-and-major-events-3306287">a function of time</a>.   However, since about 1984, with some corrections, there appears to be a double that takes place every 11-20 years.  Unless we see some rapid economic growth, or unless our country develops some austerity measures.  We are on our way to 200% debt to gdp ratios in 11 to 20 years.   Twice as much interest paid per gdp will be paid out  which will likely continue to further propel the national debt.  Which by that time will be about .76% of the world's gdp is the ratios remain the same (they wont. some countries grow/shrink faster than others).  Meaning the United states will have to work harder to sell new bonds...which is often done with higher interest rates.  And if they can't, well the treasury, under control of the federal serve, can print more money.  Either way, inflation.  Another 11-20 years, those numbers will double again to 1.52.  Another 11-20 years to 3.04.  Another 11-20 years 6.08....12.16....24.32 (about the US economy in interest payments)....48.64....and eventually US interest rates will be 99.28 of the world's gdp under a theoretical model.  In actuality the US economy will collapse long before that point, likely due to anti-austerity riots or the lack of a strong economy that lulled the American people into adopting tyranny.  It's place as a world's reserve currency will be long gone, hyperinflation will set in and I can pay off my student loans by turning in an aluminum can for recycling.

As far as what is better than the dollar.  I dare not say crypto at this point.  I balk at bitcoin at 7k each, but if the US dollar collapses that won't be a bad deal.  The wealthy are buying up land on foreign soils and underground bunkers-well obviously they are not buying up land in south Africa.  Maybe the underground bunkers is a bit too much-but tell that to the white farmers in South Africa.  The wealthy are planning for a world in a post dollar era.  Not a bad idea.  Consider buying land overseas too, and buying a mixed portfolio of world bonds (even the <a href="https://tradingeconomics.com/russia/government-debt-to-gdp">Russian Rubble</a> despite its 4% inflation rate and 7.25% interest rates on bonds), silver and gold, and perhaps even some crypto.  I think it is still too early to get back on the crypto bandwagon.   Be careful though of the Euro, the <a href="https://tradingeconomics.com/european-union/government-debt-to-gdp">Euroupean Union's</a> debt to gdp ratio is over 80%-but gradually improving.  Even The United Kingdom is in the 80s too.  

  Though the cold war ended a long time ago, US cold war spending has not ended and socialism is still widespread in Europe.  I dare say the United states could not afford financing another ground war.  It can and will if it must, but it will be ruinous in the long run. There is likely a global great depression ahead, and global coups and wars, and very few superpowers are safe. 

The other thing is, when you think about how Trump may be "bullying" other nations into NATO concessions and protectionists trade agreements.  The president likely already knows this county cannot be saved-though he should have kept that in mind before passing the omnibus spending package.