From NBC's Mark Murray
The nonpartisan Center for Responsive Politics said today that candidates, the political parties, and other outside groups will spend an estimated $2.6 billion -- yes, billion -- on this year's House and Senate races, making it the most expensive midterm election ever.

In 2002, the total price tag was $2.2 billion (and that was before the McCain-Feingold campaign-finance law banned unlimited contributions from the political parties). In 2004, it was $4.2 billion (but that was during a presidential contest). To put the $2.6 billion figure in perspective, that's more than the gross domestic products (GDP) of countries like Swaziland, Kyrgyzstan, Tajikistan, Rwanda, Togo, and Malawi, per data from the International Monetary Fund.