The top $5 bill is a United States note that is back by silver and gold, the bottom$5 bill is a Federal Reserve note that is paper monopoly money.
President Kennedy was assassinated on November 22nd, 1963 in the United States, notes he had issued were immediately taken out of circulation. Federal Reserve notes continue to serve as the legal currency of the nation. According to the United States Secret Service, 99% of all US paper currency circulating in 1999 are Federal Reserve notes.
President Kennedy knew that if the silver back United States notes were widely circulated, they would have eliminated the demand for the Federal Reserve notes. This is a very simple matter of economics. The United States Note (USN) was backed by silver, and the Federal Reserve Note (FRN) was not backed by anything of intrinsic value. Executive order 11110 should have prevented the national debt from reaching its current level virtually all of the nearly 9 trillion in federal debt has been created since 1963, if LBJ or any subsequent president were to enforce it. It would have almost immediately given the United States government ability to repay its debt without going to the private Federal Reserve banks and being charged interest to create new money. Executive order 11110 gave the United States of America the ability to, once again, create its own money back by silver and real value worth something.