Chamath Palihapitiya is launching a new SPAC, "American Exceptionalism Acquisition Corp.," offering 25 million shares at $10 each for a $250 million valuation. Investors should note his previous SPACs, including Opendoor (OPEN), Virgin Galactic (SPCE), and Clover Health (CLOV), are all down over 50% historically. This track record suggests caution is warranted when considering this new SPAC.