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Democrats in races that will help determine control of the Senate are rapidly burning through their campaign cash, whittling away their financial advantage over Republican opponents as they fend off attacks from conservative groups, according to figures released through Friday.
The spending on both sides underscores the critical role that outside conservative groups are playing as Republicans try to retake the Senate. In state after state, organizations like Americans for Prosperity, the nonprofit linked to David and Charles Koch, have kept Democrats on the defensive with a barrage of negative ads while establishment-backed Republican candidates raise money and navigate their way through primaries.