The House Ways and Means Committee will soon release the GOP’s first draft of the party’s tax proposals, and the irony is that the bill may be getting worse even as a good bill becomes more urgent. President Trump has pitched a tax-rate increase that even Democrats failed to pass, and parochial demands are shrinking the pro-growth value of the bill. Republicans seem to have forgotten the principles of sound tax policy, even the lessons of the successful 2017 reform. Most of the 26 GOP Members of Ways and Means weren’t in Congress in 2017. The intellectual capital of previous...