Who could be opposed to closing a tax loophole that allows hedge-fund and private-equity managers to treat their earnings as capital gains – and pay a rate of only 15 percent rather than the 35 percent applied to ordinary income? Answer: Some of the nation’s most prominent and wealthiest private asset managers, such as Paul Allen and Henry Kravis, who, along with hordes of lobbyists, are determined to keep the loophole wide open. The House has already tried three times to close it only to have the Senate cave in because of campaign donations from these and other financiers who benefit from it. But the measure will be brought up again in the next few weeks, and this time the result could be different. Few senators want to be overtly seen as favoring Wall Street. And tax revenues are needed to help pay for extensions of popular tax cuts, such as the college tax credit that reduces college costs for tens of thousands of poor and middle-class families. Closing this particular loophole would net some $20 billion. More after the jump. --Robert Reich