Trump supporters and some independent analysts assert that his appeal to many blue-collar whites in Rust Belt states (such as Michigan, Ohio, Pennsylvania, and Wisconsin) could pull these states’ electoral votes into the Republican column.
The problem is, there is little evidence that the non-college voters supporting Trump in the primaries are defectors from the Democrats; most have been backing GOP candidates fairly consistently, so the net addition for Trump could be small.
http://www.centerforpolitics.org/crystalball/articles/the-only-thing-that-matters/