At the end of WWII the United States had accumulated some 20,000+ tons of gold. Possibly more when counting Nazi gold that was recovered and used to help re-build Europe. The Bretton-Woods system was launched with the US dollar as a reserve currency that was fractionally backed by this gold. All other countries then pegged the value of their currency to the dollar.
Over the years, cold war and Vietnam War spending drove the US to search for more revenue and the gold just sitting in Fort Knox and ostensibly doing nothing was an attractive target for generating non- tax revenue. The US began to sell it off. Years had passed since Bretton Woods was put in place and its purpose was forgotten or ignored.
By the mid-60s the gold reserves had dwindled and other nations (particularly those grateful French) demanded payment in gold for US trade deficits and other monetary issues. In 1971 the US gold reserves had dropped by 60%, and were in acute danger of vanishing altogether. Nixon called a halt to the gold transfers in 1971 and by 1973 Bretton Woods had collapsed. Thanks to the Trilateral Commission (and the good graces of the Saudis) the petrodollar was created in the wake of the first oil shock. This re-established the dollar as the world's reserve currency as all nations had to pay for oil with dollars. Bretton Woods was seen as an anachronism.
Unfortunately all world currencies were now fiat. Further oil shocks and stagflation hit the world hard while the US was withdrawing from the world scene. The Soviet Union became more interventionist as they achieved military parity with the US.
When Ronald Reagan took office deficit spending really reared its ugly head as he cut taxes to stimulate the economy and began a military buildup that (and the Black Swan disaster of Chernobyl) broke the back of of the Soviet Empire.
After the Gulf War, Bush 41 raised taxes and was followed by Bill Clinton who raised taxes further and used "the peace dividend" (our Navy went from almost 600 ships to less than 300 for example) to actually create a budget surplus.
Bush 43 cut taxes but was soon confronted by 9/11 and the global war on terror. US budget deficits exploded toward the trillion dollar mark and was followed by Obama and now Trump with more of the same. For almost 20 years now the world has been truly living beyond its means.
We are due for a comeuppance.
How do we get out of this mess? One could project a single world currency (probably electronic and cashless). I am not an economist but historically it should be backed by gold so as to contain irrational transactions, particularly those of a more speculative nature. This would require pooling of gold reserves and confiscation of privately held gold. One world currency leads to one world government which leads to severely constrained freedoms, confiscation of all privately held property AND SOCIALISM with all its miseries.
Over the course of a century or so military forces would vanish and be replaced by robust police forces to keep everybody under control. Gradually productivity would be sapped and civilization will collapse when we don't produce enough goods and food to sustain it.
Alternatively we could wait out the comeuppance and try to rebuild as the world tumbles into a Somalia- Venezuela style anarchy.
All this because the world (particularly the US) lost sight of gold's real purpose - our money of last resort.
The break-point in history was the decision to abandon gold in favor of oil. Had the world the courage in 1973 we could have rebuilt the gold reserves. Perhaps it is not too late. Doing so would require pooling of the worlds gold reserves, all newly mined gold going to the new reserve and the halt of all speculative trading in it. As a last resort confiscation of privately held gold whether as bullion,coins, or jewelry. The end of central banking as it exists today may help.
A World Gold Council chart shows that the beginning of the sell off of American gold reserves began at the end of the Eisenhower administration and continues right through both Kennedy and Johnson - (who opted for both guns and butter with Vietnam and his Great Society programs). The selling and other transfers of 60% of American gold reserves took place over 10 years and finally stopped in 1969 as Nixon took office and DeGaulle stepped up his demands for more American gold. So don't blame Nixon for the end of Bretton Woods. He only stopped the hemorrhaging. Had he not stopped it nothing would be left to build on.