The author is writing to Mr. Jones about a proposed law regarding tax deductions for employee contributions to pension plans. The author believes that making voluntary contributions deductible but not mandatory contributions would be a bad law. They suggest restructuring pension plans to make mandatory contributions voluntary instead. They also suggest excluding employee contributions up to the Social Security contribution figure for federal workers not covered under Social Security. The author advises against unequal deduction limits for those covered under a pension plan and those who aren't, as it would complicate matters. They encourage keeping the deduction limits equal.