Sen. Rob Portman, R-Ohio, trailed his likely Democratic opponent, former Gov. Ted Strickland, by 3 points in a poll conducted for a Democratic super PAC and provided first to CQ Roll Call.
Strickland was favored by 46 percent of those polled, while 43 percent favored Portman, according to the poll conducted for Senate Majority PAC by Harstad Strategic Research.
The Ohio Senate race is a top Democratic target in 2016, when the party will seek to net the five seats necessary to ensure Senate control. Democrats view the Ohio race as a top pickup opportunity as President Barack Obama carried the state in 2008 and 2012.
Portman, however, is one of the best fundraisers in the Senate. His campaign reported raising more than $2 million in the third quarter, and will report more than $11 million in cash on hand as of the end of September.
Strickland has yet to post his third-quarter haul, but as of June 30 had $1.2 million in the bank.
Strickland faces a primary against Cincinnati City Councilman P.G. Sittenfeld, but Sittenfeld is a heavy underdog.
Republican groups such as Americans for Prosperity, the conservative Koch brothers-backed super PAC, as well as Portman's campaign, have already spent millions on this race both to boost Portman's image and attack Strickland.
The poll tested voter familiarity with the Koch brothers, and found 36 percent were familiar with the Kansas-based businessmen. Of that 36 percent, 3 to 1 viewed them unfavorably.
The poll surveyed 813 likely voters via live telephone from Sept. 10 to Sept. 16. It has a margin of error of 3.4 percent.
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