"Treasury's official position went from opposed to to supportive."
Maybe Feingold should have traded his opposition to preserve Volcker.
Democratic leaders and the White House have long considered Brown the linchpin of financial reform. Because of Feingold's and Cantwell's opposition, Democrats had to rely on a small handful of Republicans to push the bill over the finish line. Brown was believed to be the 60th, filibuster-breaking vote, and ultimately won his exemption.
Opinions vary as to whether top Democrats on the Hill and in the White House did enough to persuade Feingold and Cantwell to change their votes, which would have robbed Brown of much, if not all of his leverage. Some place the blame for the outcome at Feingold and Cantwell's feet: Brown wouldn't have won his loophole if one or both of them had been willing to flip their votes in exchange for a more restrictive Volcker rule. Others argue that the administration always places too much faith in moderate Republicans and simply sought to avoid antagonizing Brown, who will likely be a swing vote on future legislation.