Between ObamaCare, Iran and last quarter's uptick in U.S. economic growth, taxpayers these days may be distracted from several dangers to come. But households from the United States to Europe and Japan may soon face fiscal shocks worse than any market crash. The White House and New York Mayor-elect Bill de Blasio aren't the only ones calling for higher taxes (especially on the wealthy), as voices from the International Monetary Fund to billionaire investor Bill Gross increasingly make the case too.

In his November investment...