Goldman Sachs is lobbying hard to kill a provision in financial-industry overhaul legislation requiring big banks to sell off their derivatives trading businesses, and rival banks are welcoming the help, shrugging off attacks on the firm by lawmakers and securities regulators.

Goldman's lobbying could put Democrats and the White House, which is lukewarm on the provision, in a difficult position. With congressional elections looming in November, lawmakers don't want to appear supportive of Goldman or Wall Street.