The group spent more than $104 million on federal races in 2012. Most of that money -- $95.8 million -- was spent against Democrat candidates, according to the Center for Responsive Politics, which tracks political spending by candidates and groups.
Harper Polling is a relatively new polling firm, started by McCleary in December 2012.
Democrat consultant Mike Plant said because the firm is new, it's difficult to say how accurate their results will be. The poll was conducted using a computerized system, not human operators, which are the "gold standard" of political polling, he said.
Plant said Public Policy Polling also uses computerized systems and has a reputation of running some of the most accurate polls in the nation.
"I think it just remains to be seen in terms of what their track record will be," he said.
Public Policy Polling conducted its own poll of the West Virginia Senate race last month, and also found Capito had a significant lead over Tennant: 50 percent of poll respondents said they would vote for Capito, while 36 percent said they would pick Tennant.
Capito's approval rating was a bit lower in Public Policy Polling's survey, however, with 45 percent saying they had a "favorable" opinion of the longtime congresswoman. Harper Polling's survey showed 50 percent had a favorable opinion of Capito.
Tennant's approval rating was the same in both polls -- 39 percent -- although Harper Polling found 27 percent held an unfavorable opinion of the candidate, and 34 percent were not sure.
Public Policy Polling's survey found 32 percent had an unfavorable opinion of Tennant, and 30 percent were unsure.