How to use "insufficient" in a sentence

Instead of honoring this sacred obligation, America has given the Negro people a bad check, a check which has come back marked "insufficient funds."

We refuse to believe that there are insufficient funds in the great vaults of opportunity of this nation

Considering the high price that they had paid for the pathetically insufficient information they had obtained, he couldn't tolerate the prospect of all their pain and fear and anxiety having been for naught.