When Mitt Romney faced questions on the campaign trail four years ago about investments in firms engaged in embryonic stem cell research, the presidential candidate had a ready explanation -- he was unaware because his vast financial portfolio was under the control of an independent trustee. Last week, Romney's campaign pulled out the same explanation when ABC News sought details about the candidate's holdings in the Cayman Islands, a notorious offshore tax haven. "We remind you that Gov. Romney does not choose anything; these are BLIND TRUSTS," a campaign official wrote in an email. But government ethics experts and election...