The recent joint statement on U.S. tax reforms by Republicans in Congress and the Trump administration is clear about its goals of protecting American families, jobs and businesses, but brings little clarity to how those could be achieved. Its authors want lower taxes for households and businesses, but don’t explain how the government would recoup the revenue losses those would entail. They are clear in rejecting two proposals doing the rounds — a border adjustment tax and a consumption-based tax. Trump’s campaign assurance that lower taxes would spur economic growth sufficiently to recoup the lost tax revenues doesn’t add up, according to Kent Smetters , Wharton professor of business economics and public policy. He is also faculty director of the Penn Wharton Budget Model , an interactive analytical tool that allows users to weigh the potential impact of individual policy proposals.…