Non traditional threat to US

In my opinion the most pertinent Non-traditional threat to the US is the economy. It is the single most important, globalized, and un-accounted for problem in the US. The current problem is so bad that the US economy is days away from a (partial) default. This would be the first default since possibly the 1700’s at the founding of the nation. The problem with this is the US green back is the reserve currency of the world (all or most investments are made in US dollars). If the US defaults it will cause a ripple effect that will make the 2008 global financial crisis look small in comparison to the global catastrophe that will occur. The reason most investments are in US dollars is because dollars have historically been the most stable currency in the modern age.
The US defaulting on its debts has both internal and external effects. The total of US government debt is over $ 16.9 trillion. (US Debt Clock) Of that debt, $ 4.8 trillion is owned by governmental agencies. This includes agencies such as the social security (holds over $2.5 trillion dollars). Of the public debt, foreign investors own $5.7 trillion. Keep in mind this is just the actual government debt; effects of a default would be much bigger. The US reached its debt ceiling in 2012. The US constitution - 14th Amendment, Section 4 - directly forbids the government from defaulting on its debt. Thus to cope with the debt ceiling being reached the government has been taking extraordinary measures in order to pay their debts (for instance suspending investments on individual pension funds). When these measures are exhausted, the government will not bring on a global economic collapse as they default on all their bonds. They will just be forced to balance the economy - to match their spending with their collected revenue. This is a very different issue (still with its problems) to a full default.
What is important is that a full default is likely to not happen. The brinksmanship between the rogue Republicans