THE OTHER SHOE By MARK DeCAMBRE September 16, 2008 -- Insurance giant American International got whacked with downgrades from all three major ratings companies last night even as it huddled in intense negotiations with state and federal regulators trying to raise tens of billions of dollars in capital. Standard & Poor's, Moody's and Fitch leveled downgrades on AIG - an event that could mean the ailing insurer must raise at least $12 billion in additional capital to appease skittish companies known as counterparties that do trades with the insurer. S&P downgraded the insurer's long- and short-term rating to A- from...