Story highlights Clinton and Kaine will reach out to disaffected Republicans in Pennsylvania and Ohio

Around 20% of Republicans have an unfavorable view of Trump

Clinton and Kaine will also reach out to white, working class voters

Hatfield, Pennsylvania (CNN) Hillary Clinton and Tim Kaine are on a three-day, 600-mile bus tour through right-leaning Rust Belt counties, with at least a partial goal of winning over some Republicans who are put off by Donald Trump.

The trip through Pennsylvania and Ohio, which started Friday, looks to take advantage of a problem within the Republican Party: That around 20% of Republicans have an unfavorable view of their newly-minted nominee.

But the trip also hints at a problem within Clinton's base, as well: White, working class voters, especially those hurt by globalization and manufacturing plants are drawn to Trump's message of economic security and cracking down on immigration.

Clinton's top aides see both Pennsylvania and Ohio as key states for Trump, where he must outperform how Mitt Romney did in 2012. But Democrats are bullish that Trump could do just that, especially if longtime Democratic voters overlook Trump's braggadocios demeanor and vote for him in November.

By reaching out to Republicans -- as the campaign did at the Democratic National Convention this week and will do in the coming days -- Clinton's team are also looking to shore up support with Democrats.

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