sentence1: When the trust fund begins running cash deficits in 2016, the government as a whole must come up with the cash to finance Social Security's cash deficit by reducing any projected non-Social Security surpluses, borrowing from the public, raising other taxes, or reducing other government spending.
sentence2: In 2016 the entire government will have to find the money to finance the fund when Social Security is forced to run on cash deficits.