I'm pretty sure he was referring to this:
No, he was not referring to the Virginia governor, although he did make that claim during his state of the union address, regarding comments by the Va. governor. At the Wisconsin rally, he was referring to actions he said the Democratic governor of Wisconsin would take in vetoing a GOP backed bill before the Wisconsin legislature:
https://slate.com/news-and-politics/2019/04/trump-abortion-baby-wrapped-blanket-execute-baby.html
"Trump went on to falsely characterize what he said an “extreme late abortion” would entail in horrifically graphic—and not to mention misleading—language. “Your Democrat governor here in Wisconsin, shockingly, stated that he will veto legislation that protects Wisconsin babies born alive. Born alive,” Trump said in a disapproving tone. “The baby is born, the mother meets with the doctor, they take care of the baby, they wrap the baby beautifully, and then the doctor and the mother determine whether or not they will execute the baby.” Trump then put on an incredulous tone. “You hear late term, but this is where the baby is born, it’s there, it’s wrapped, that’s it,” Trump said as he made a guillotine motion with his hand, as if he were implying that the baby’s head would be sliced off."
See also:
https://www.usatoday.com/story/news...ter-failed-abortion-fact-check-ap/1186702001/
https://www.newshub.co.nz/home/worl...s-can-execute-babies-after-they-are-born.html
His comments have been widely condemned on social media, largely for his use of the word 'execute' and for the facts being inaccurate. Laws in the US already protect newborn babies even if they survive an abortion.
Democratic Governor Roy Cooper, who also vetoed the bill, said all it did was "criminalise doctors for a practice that does not exist".