Washington (CNN) - One of this election cycle's major third party groups is announcing it will spend more than four million dollars in the next week in its largest media buy of the season spread across eight of the key Senate battlegrounds.
In an effort to help elect Republicans in these races, American Crossroads will spend almost $800,000 in Colorado and $350,000 in Nevada while its affiliate Crossroads Grassroots Policy Strategies (GPS) is buying time in Illinois, Washington state, Missouri, Kentucky and Pennsylvania.
While Crossroads, an independent expenditure committee, does have to disclose its donors, Crossroads GPS, which is registered as its nonprofit arm, does not have to divulge those names.
American Crossroads says it raised $14 million between Aug. 20th and Sept. 20th. The two Crossroads groups have said they plan to spend $50 million this season. They are expected to announce their first spending in House races sometime in the next week.
Last week Crossroads announced a get out the vote effort in West Virginia - its ninth - in which stalwart GOP voters and independents will see early voting notifications, absentee ballot alerts and mail and phone calls in the final 72 hours.
Crossroads' spending is just the latest salvo in the high stakes efforts by third party groups supporting both parties in light of the Supreme Court Citizens United ruling which said corporations and unions could spend unlimited amounts on campaign-related matters. In many cases these groups are not required to disclose their donors because of the way they are set up.
These groups are expected to spend an estimated $500 million on the mid-term elections, according to an estimate by the Center for Public Integrity. The center expects GOP-aligned groups will likely outspend their Democratic counterparts by more than 30%.
So far in House and Senate races GOP-allied groups have spent $43 million on television ads while Democratic-allied ones have invested $17 million, according to the Campaign Media Analysis Group, CNN's consultant.
To try to compensate for the large influx of GOP supported money, unions are trying to help boost their Democratic allies. The Service Employees International Union and National Nurses United this week started ad campaigns against several candidates, including Nevada Republican senatorial nominee Sharron Angle and California Gubernatorial candidate Meg Whitman.