Tom Cotton to Challenge Mark Pryor #ARSEN

Pryor is already running advertisements for his re-election. (Chris Maddaloni/CQ Roll Call File Photo)

Freshman Rep. Tom Cotton, R-Ark., will announce his candidacy next week to challenge Sen. Mark Pryor, arguably Democrats' most vulnerable senator of the cycle.

The Associated Press reported Wednesday that Cotton would make his campaign announcement Aug. 6 at an event in his hometown of Dardanelle.

(See also in Roll Call: Pryor Can't Escape 2010 Comparison)

In an email with CQ Roll Call, Cotton spokeswoman Caroline Rabbitt would only confirm that the congressman is holding the event. Cotton purchased an ad in the Wednesday issue of the Yell County Record announcing an event at the Dardanelle Community Center.

"On Tuesday, Tom is inviting his hometown and all who have supported him along the way to hear about his fight to represent Arkansas's values in DC," Rabbitt said. "He looks forward to sharing his plans to continue that fight in the coming year."

His candidacy in this Republican-trending state means the race will likely become one of the most competitive in the country. National Republicans touted Cotton as a top recruit who they believe can defeat Pryor, who did not have a Republican challenger in 2008.

Pryor has turned in two straight strong fundraising quarters and had $3.9 million in cash on hand as of June 30. Cotton had just more than $1 million at the end of the second fundraising quarter.

Democratic outside groups have already targeted Cotton on TV, while conservative groups have already gone after Pryor. The senator launched his own TV ad at the end of May.

The race is rated a Pure Tossup by Rothenberg Political Report/Roll Call.