He also knows the media will be all over this and spread public perception of her false claims of heritage.
Trump can take two wires and cross them to make sparks like no one else.
Given his track record against opponents, I give him the benefit of doubt.
I fully expect to see Elizabeth Warren, sullenly sitting in a teepee, saying, "He broke me!"
You are correct. Trump is planting the seeds of her political destruction should she run in 2020. Everybody will be asking her to prove her claimed Native American heritage.
She may not even run as a result.