Michawn Rich, a Portman spokeswoman, said the poll demonstrates “momentum continues to grow behind our campaign.”
But David Bergstein, a Strickland spokesman, said all of the polls “consistently show is that after Senator Portman and his allies have spent over $30 million against Ted they’ve failed to put this race away.”
While the poll contains a blizzard of grim news for Strickland, the race could be closer than Quinnipiac shows. Of those polled in Ohio, 34 percent said they are Democrats, 30 percent are Republicans and 29 percent independent.
But unlike many polls, Quinnipiac does not adjust the results for what its researchers believe will be the likely partisan breakdown, a technique known as weighting the sample. Instead, Quinnipiac calculates the percentage of Democrats and Republicans based on the answers given during the phone interviews with voters.
By contrast, other surveys nationally suggest a higher percentage of Democrats will vote, in part because a number of Republicans are so irritated with Trump’s campaign they will not show up to vote. If that happens in Ohio, Strickland could close the gap.
The race between Portman and Strickland is among a handful of races which will determine which political party controls the U.S. Senate next year. Republicans currently hold 54 seats to 44 for the Democrats, although independents Bernie Sanders of Vermont and Angus King of Maine caucus with the Democrats.
In addition to Ohio, Democrats are hoping that if Democratic presidential nominee Hillary Clinton defeats Republican Donald Trump by a wide margin, they can win Republican seats in Pennsylvania, Wisconsin, New Hampshire, Indiana and Illinois.
“Portman in Ohio may have a strong enough lead to escape the Trump effect,” Brown said.
Quinnipiac released polls of Senate races in Florida and Pennsylvania, showing Republican Sen. Marco Rubio with a narrow lead over his likely Democratic challengers while Republican Sen. Pat Toomey of Pennsylvania is trailing Democratic challenger Kate McGinity by three points.
Democrats in Florida will choose their Senate nominee in a primary later this month.
A Quinnipiac poll last month showed Portman leading Strickland by seven percentage points. But unlike today’s poll which relied on likely voters, last month’s poll was among registered voters, meaning it is difficult to compare the two.
Strickland, who served as governor of Ohio from 2007 through the end of 2010 when the nation was mired in a deep recession, has been overwhelmed by Portman’s huge advantage in fundraising. Last month, Portman reported having $13 million in his campaign treasury compared to $4 million for Strickland.
The poll of 812 Ohio voters using traditional telephones and cell phones has a margin of error of plus or minus 3.4 percent.