CLEVELAND, Ohio -- A new national poll shows Democratic U.S. Sen. Sherrod Brown of Ohio holding a big lead in his re-election campaign.

The poll, released Wednesday and commissioned by Politico and the AARP, found Brown leading Republican Rep. Jim Renacci by a 47 percent to 31 percent margin. It also found Republican Mike DeWine just ahead of Richard Cordray in the Ohio governor's race, 39 percent to 38 percent.

The poll also found President Donald Trump has a 43 percent approval rating among voters in Ohio, with 53 percent disapproving.

The poll was conducted online of 1,592 registered voters between Sept. 2 and Sept. 11, according to Morning Consult, the pollster Politico and the AARP hired. The poll's margin of sampling error is 2 percent. The election is in November.

Why the results might seem confusing

A different poll released last week, commissioned by Innovation Ohio, a liberal Columbus think-tank, showed Brown leading Renacci by just 4 points, 46 percent to 42 percent. The same poll, conducted by Change Research, a Democratic polling firm, showed DeWine leading Cordray 45 percent to 43 percent.

Like the Politico/AARP poll, the Innovation Ohio poll was conducted online. This can pose problems in and of itself, since phone polls with live interviewers are seen as being more accurate.

But the Innovation Ohio poll was different in that it sampled "likely voters," meaning it attempted to screen out people who were unlikely to vote. The Politico/AARP poll simply asked registered voters.

Drilling down into the numbers, some aspects of the Politico/AARP sample suggest the survey disproportionately includes Democratic-leaning voters. For example, it says of the poll respondents, 39 percent said they voted for Donald Trump in 2016, while 38 percent voted for Hillary Clinton. (Trump actually won Ohio 52 percent to 44 percent.)

"A distorted poll that underrepresents Republicans and uses registered voters instead of likely voters does not illustrate the realities of the race," Leslie Shedd, a Renacci campaign spokeswoman, said in an email. "A public poll released just last week, in addition to our internal polls, shows a tight race."

FiveThirtyEight, the polling website, gives Morning Consult a B- for accuracy, while Change Research gets a C+.

Why they still matter

Even if the Innovation Ohio poll more closely reflects political reality -- we generally view Brown as having a comfortable lead but not an insurmountable one -- many more people are likely to read the Politico poll, given the national publication's broad reach among political junkies.

And for Renacci, national perception matters. Due in part to public polling that's generally shown Brown with a double-digit lead, and due in part to private polling from Republican organizations that apparently haven't painted a much rosier picture, Renacci has struggled to gain financial traction for his campaign.

Renacci has trailed Brown in fundraising. But more than that, the deep-pocketed national Republican groups that could help him out have passed over Ohio in favor of other states with Senate races viewed as more competitive. Tellingly, Republican Senate President Mitch McConnell on Tuesday told reporters he's closely watching nine Senate -- none of which are Ohio.

Perhaps because of his need to be stingy with his campaign funds, Renacci has yet to air TV ads heading into this final leg of the election, meaning many Ohioans likely still don't know who he is.

In a Sept. 11 interview with National Journal, a Washington, D.C. publication, Renacci claimed his campaign's internal polling shows the race as effectively tied. But, he also alluded to the need to attract attention to his campaign.

"The plan is to continue to be in Ohio almost every day that I can be. It's to go from event to event to event. It's to make sure that the media's picking up this race, that people know it's important," Renacci said.

Why we care about polls



We don't write about every poll, but we do make note of them, looking for larger trends. They don't predict the race's outcome as 2016 showed, but they do help set expectations, likely accurately framing August's special election for Ohio's 12th Congressional District as a close race.

And particularly because of Renacci's particular need to impress on a national level, any poll can make a difference.