It’s said taxes are eternal. Maybe not all of them. In an about-face the Obama administration has decided to back repeal of a mostly-ignored 1989 tax on the personal use of company cell phones. Just last week the IRS put out feelers on ways the law might be enforced. Instead, what the agency got was heat from businesses and individuals. Now it’s backing off. Good move. The tax is hard for people to calculate given today’s varied cell phone usages and even harder to enforce. It’s a relic of a time when cell phones were a perk for upwardly mobile Americans. That era obviously has passed, and so should the tax.