While Mitt Romney struggles to explain his retroactive retirement from Bain Capital, the company he created keeps offshoring U.S. jobs. Among them: the jobs of 170 workers in Freeport, Ill., now training the workers who will replace them when Sensata moves their jobs to China. SEC filings reveal that the U.S. share of Sensata’s workforce has been dropping ever since Bain acquired it in 2006. And the Sensata workers aren’t Bain’s only recent casualties.