West Virginia's Republican Attorney General Patrick Morrisey has scheduled a political event Monday where he's expected to announce his candidacy for the U.S. Senate seat now held by Democrat Joe Manchin.
Morrisey, re-elected to a second term last year, is also chairman of the national organization of Republican attorneys general.
The group's Mountaineers Are Always Free PAC bought almost $6.8 million in ads promoting Morrisey for a second term and attacking his opponent, outspending either one.
The Republican Attorney Generals Association and Morrisey have been involved in challenges to federal regulations under the Obama administration.
West Virginia's Republican Congressman Evan Jenkins, re-elected to a second term last year, is also running against Manchin, the former governor elected to the Senate in 2010.