Kasich Trump convention

In this Feb. 6, 2016, file photo, Ohio Gov. John Kasich, left, and Donald Trump, right, speak to reporters after a Republican presidential primary debate hosted by ABC News at Saint Anselm College in Manchester, N.H.

(Matt Rourke, Associated Press)

CLEVELAND, Ohio -- A new poll released Monday tells a story for Republicans of what could have been.

And at the same time, it tells a familiar story about this year's presidential election -- voters in Ohio dislike Hillary Clinton, but seem to dislike Donald Trump just a little more.

The Monmouth University poll found Clinton holding a narrow lead over Trump, 43 percent to 39 percent. (The poll shows Libertarian Gary Johnson pulling down 10 percent, although it's unclear if the survey identified him as a "Libertarian" -- he will appear as an "Independent" on the November ballot in Ohio.)

That finding is consistent with all four state polls released since the conclusion of last month's Republican and Democratic national conventions, including a poll released Sunday from CBS News/YouGov that found Clinton leading Trump 46 percent to 40 percent.

"Ohio has been nip and tuck for nearly every presidential election since 1992," Patrick Murray, the director of the Monmouth University Polling Institute, said in a statement. "As of right now, it looks like that tradition will continue."

But given a hypothetical choice between Clinton and Republican Ohio Gov. John Kasich, 57 percent said they'd pick Kasich, with just 33 percent choosing Clinton.

Ohio is a key battleground state in every presidential election that holds particular strategic value for Republicans. Kasich, who ran a presidential campaign that positioned him as more of a moderate -- handily beat Trump in the state's March GOP primary 47 percent to 36 percent, but failed to win in any other state and finished a distant third in the race.

The poll also found that only 17 percent of Ohioans think less highly of Kasich for not backing Trump, his party's nominee. Thirty-eight percent said they thought more highly of him, with 44 percent saying it made no difference.

Monmouth didn't ask respondents what they think of Kasich. But like previous polls, most said they held unfavorable opinions about Trump (58 percent) and Clinton (51 percent.)

There's another sign in the Monmouth poll that suggests -- despite Clinton's consistent, but narrow polling lead -- that this year might otherwise have held a built-in advantage for Republicans in Ohio.

The poll shows GOP Sen. Rob Portman leading his Democratic challenger, former Gov. Ted Strickland, 48 percent to 40 percent. That basically replicates Sunday's CBS/YouGov poll that showed Portman leading Strickland 46 percent to 39 percent.

That's despite 52 percent of respondents saying they didn't know enough about Portman to form an opinion about him, even as Portman and his allies have spent more than $31.7 million on, among other things, touting Portman's record on curbing heroin abuse and on trade.

The Monmouth poll sampled 402 likely Ohio voters using live telephone callers, with a margin of error of plus or minus 4.9 percent. The CBS/YouGov poll surveyed an online panel of 997 likely Ohio voters, and has a margin of error of plus or minus 3.9 percent.