A new report says campaign spending for U.S. congressional elections this year could be close to $4 billion, breaking a spending record for a midterm vote.
The study, from the nonpartisan Center for Responsive Politics, says the amount of spending by candidates, political parties and independent groups will be about $1 billion more than the previous record set in 2006.
The group attributes the increase to two main factors -- a large number of competitive races and recent federal court decisions allowing corporations and organizations to spend as much as they want on political messages.
According to the study, spending has been about even between Republican and Democratic candidates and their parties. But it says Republicans, the minority party in Congress, have benefited more from funding by outside groups.
Recent polls show Republicans poised to win enough seats in the vote next week to take control of the House of Representatives. They are also expected to make gains in the Senate.
All 435 seats in the U.S. House of Representatives and 37 of the 100 Senate seats are at stake in the November 2 vote.