"I like right to work. My position on right to work is 100 percent," Trump said in a radio interview in South Carolina last month.
The text campaign on which the ads will be modeled featured a quote from Trumka, hitting Trump on right-to-work, and characterizing him as racist: "Donald Trump's bigoted comments are bad enough. Now, he supports right to work. Tell him right to work is wrong for working people."
There are some signs Trump's message is resonating beyond the 20 to 30 percent of rank-and-file union members that vote Republican, attracting political independents and even some frustrated Democrats.
"But I think when all is said and done, when unions put their programs into gear, in person and one-on-one in homes and in their communities, union members will vote overwhelmingly for the Democratic nominee," Rosenthal said. "Trump might have some appeal right now, but once you start to peel away his record - his manufacturing in China, his relationships with unions - he's a pretty good target."