Yahoo Finance - Debt ceiling: What a US default could look like
Excerpt:
It is impossible to predict exactly how things would unfold if the US takes the unprecedented step of defaulting on its debt in June.
What seems likely, experts tell Yahoo Finance, is that America and the world would experience a shocking initial crisis followed by more economic damage with each passing day. Markets could plunge just as Social Security and Medicare become unable to distribute money to those who need the government safety nets.
It's also clear US policymakers would have to make perilous choices about millions of other bills the federal government has to pay each month, especially if they want to buy more time and mitigate the fallout.
Who would be paid first: Treasury bondholders or retirees? Veterans or tax-refund recipients? Defense contractors or federal employees?
If bondholders get special treatment instead of Social Security recipients, the US would effectively be paying wealthy investors around the world “instead of paying off your grandma,” said Kroll's Global Chief Economist Megan Greene. “That's pretty politically toxic.”
https://finance.yahoo.com/news/debt-ceiling-what-a-us-default-could-look-like-170025214.html