Ahead of his rally Monday night in Akron, Ohio, a new Monmouth University poll shows Donald Trump within striking distance of Democratic presidential hopeful Hillary Clinton in the Buckeye State.

Clinton leads Trump 43 to 39 percent among likely general election voters in Ohio, putting Trump inside the poll's 4.9 percent margin of error. Ten percent of voters currently support Libertarian nominee Gary Johnson, while 8 percent of voters remain undecided.

Independent voters split evenly for Trump and Clinton, with both candidates drawing 35 percent support, while 20 percent back Johnson.

Both Clinton and Trump are struggling to do as well as their predecessors, President Obama and Mitt Romney, did with the voters who made up their bases in 2012. Fewer than 75 percent of black, Hispanic and Asian voters currently back Clinton, while Obama received 84 percent support among the same bloc in 2012. Similarly, only 45 percent of white voters support Trump compared with 57 percent who backed Romney four years ago. Trump continues to trail Clinton among white women in Ohio, a demographic Romney won by 7 percentage points in 2012.

While both nominees have made a strong pitch for working-class voters in the Rust Belt, slightly more Ohioans (42 percent) view Clinton as the candidate who is "looking out for the little guy." Thirty-eight percent of voters say Trump would do a better job at this.

Ohio Gov. John Kasich's refusal to endorse Trump, which has frustrated some Republican leaders, does not appear to be hurting him among his own constituents. Only 17 percent of voters said they think less of him because of his non-endorsement, while 38 percent said the Republican governor's decision has made them think more highly of him and 44 percent were indifferent.

The Monmouth University poll of 402 Ohio voters was conducted between Aug. 18-21, the same week Trump made his first direct appeal to African-American voters and began delivering teleprompter speeches at his campaign rallies.