PROVIDENCE, R.I. - Why would Democrats in Hawaii give money to a U.S. Senate candidate in Rhode Island? That question is creating a furor around Rhode Island Secretary of State Matt Brown, who is running for the Senate. At issue is whether his campaign engaged in "donation swapping," a practice experts say is a common and legally dubious means of skirting the federal limits on political contributions. Late last year, Brown received $25,000 from the state Democratic parties in Hawaii, Maine and Massachusetts. Shortly afterward, four of his top donors gave $30,000 to those parties. The donors had already given...