The Dubai government, whose purchase of six American ports sparked a political furor, is poised to acquire substantial stakes in Citigroup and other New York-based banks mired in subprime mortgage debt. Omar bin Sulaiman, the governor of the Dubai government's investment arm, DIFC Investments, is currently on a spending spree, spurred by the bargains that have resulted from the low value of the dollar and the sinking of the stock markets caused by the subprime mortgage crisis. Last year, Dubai caused a political storm in America when its Dubai Ports World company acquired six major American ports as part of...