These are some of the people who'll be impacted if the U.S. defaults on its debts

Cole Lyle (left), a Marine Corps veteran and executive director of the veterans advocacy group Mission Roll Call, says a U.S. default would have devastating consequences for former military members who stand to see their benefits suspended. (Courtesy of Cole Lyle)

Veterans, seniors and government employees: These are just some of the people who stand to be impacted if Congress fails to raise the debt ceiling.

Treasury Secretary Janet Yellen warns that without additional borrowing authority, the U.S. could run short of cash to pay its bills as early as June 1.

A default would send shock waves through the global economy and financial markets.