Like most Americans, I took Social Security for granted for most of my life. Until about 10 years ago, I carried a vague idea that the program had been promised to Moses on Mount Sinai (whaddya mean Grandpa didnt have a Social Security number until he was 27?). Combined with that assumption was my hazy belief that its benefits would dry up by the time I reached my sixties.My eyes were opened when I was asked to literally write the book on Social Security in 2015. (Forgive the shameless plug.)In researching and writing that book, I learned that Social Security represents the best of American federal policyand that the widespread misunderstanding of this program puts itand usin peril.Since then, I have become a dedicated Social Security fangirl who believes its important for all Americans to better understand and appreciate this program. Heres why.The gritty origin storyThe Social Security Act was signed into law on August 14, 1935, a date that dedicated students of history will recognize as smack-dab in the middle of the Great Depression. Thats not a coincidence. America faced a staggering 25% unemployment rate during the 1930s, and more than half the elderly population lived in poverty. This was not the economic reality Americans wanted for their grandparentsor themselves.In 1934, President Franklin D. Roosevelt appointed Labor Secretary Frances Perkins (the first woman appointed to a presidential cabinet and a stone-cold badass) to be chair of a newly formed committee on economic security. Perkins created a report that included a legislative proposal for what would become the Social Security Act.An elegant designA common misconception about Social Security is that you are contributing money to your future benefits. You might assume there is an account with your name on it where your contributions go to wait until you retire. Its an understandable mistake since thats how your 401(k) and other retirement accounts work.But Social Security was designed as a direct handover from current workers to current beneficiaries. By setting up the program so that people currently working made contributions to people currently retired, the government does not have to hold or invest money for the future.This design means that Social Security can never run out of money. The money is consistently transferred from current workers to current beneficiaries, which means there will be money for benefits when you retire.Yes, you.A history of tinkeringSince Social Security is federal legislation, its subject to change as the economy and society change. For example, the original Social Security Act excluded coverage for many jobs, including agriculture, domestic work, teachers, librarians, and nurses. The program was expanded to include these in 1950.Some other major changes included the 1962 legislation that allowed dependent husbandsnot just wivesto receive benefits after becoming widowed, and the 1972 introduction of cost of living adjustments (COLA) to benefits. One of the biggest changes occurred in 1983, in anticipation of the future mass retirement of baby boomers.Between 2011 and 2029, approximately 10,000 boomers turn 65 every single day, which is a rate of retirement that Social Security was not originally designed to handle. The 1983 legislative changes to Social Security gradually raised the age of full retirement for boomers and subsequent generations, lowering the cost of their benefits.Future planningThe 1983 legislation, like every change to Social Security, increased the programs complexity, which is a common source of frustration about the program.While changes to the program have sometimes led to unintended consequences, every single legislative decision reflects good faith, good intentions, and long-term planning.Consider the fact that in 1983, the oldest boomers were in their thirties, but Congress was already looking ahead to their retirement. Thats because the United States is the only country in the world that uses 75-year projections for its social insurance program. Most other countries use a shorter timeline. Only Japan, with a 95-year projection, uses a longer one.This kind of forethought and projection means were (theoretically) able to avert oncoming problems decades before they arrive.The greatly exaggerated reports of Social Securitys demiseWhen I tell a contemporary that they can count on Social Security in the future, they often struggle to believe meand for good reason. You dont have to go far to find headlines describing the programs imminent insolvency.Heres the reality: The Social Security Trust Fund will run out of money in 2035. At that point, the Social Security program will only be able to pay out approximately 83% of promised benefits. Most people focus on the run out of money half of that sentence, glossing right over the youll get 83% of your promised benefits part.While a 17% reduction in your promised benefits is crappy, its a hell of a lot better than no benefits at all. Thats why I encourage Americans to remember that Social Security is facing an imminent shortfall, not an imminent bankruptcy.To avert the shortfall, Congress just needs to make some adjustments to the legislation. (Yeah, Im not holding my breath, either). But this is a fixable problem, if we as a country are willing to do the work.The real threat to Social SecurityI like to tell people that if Social Security benefits are not there for us when we retire, it means we have bigger problems than retirement income.Because I have a waggish sense of humor, Ill often name the kinds of fantastical and unlikely threats that would truly dismantle Social Securitya meteor heading straight for Earth, a robot apocalypse, or a fascist takeover of the American government.In other words, Social Security is about as close to a financial guarantee as we can have, but that doesnt mean its immune to threatsespecially the outlandish threats that are a lot less funny than they used to be.As a federal program, Social Security can be fundamentally changed or even rescinded with the stroke of a pen. And its more likely this will happen if the American citizens who are the beneficiaries of this amazing, flawed, and life-saving program believe the lies about it.This is why Ill spend Social Securitys 90th year touting its merits to everyone who will listen. The better we understand and claim Social Security as our own, the more secure it will beeven in the unlikely event of a zombie apocalypse.