The swine flu outbreak that now threatens to become a global crisis is eerily similar to the 1918 flu pandemic that killed 675,000 Americans. Conservative estimates put the worldwide death toll at 40 million. Health services were quickly overwhelmed while the U.S. government struggled to meet its obligations to provide men and materiel for World War I. With today’s underfunded health care system and massive government debt, are we in for a repeat of 1918? American History magazine’s story “The Enemy Within” looks back at those deadly days.