What do you mean? Have the tax rate on CP be tied to a certain percentage based on the current value of today's dollar? So higher inflation equals a lower rate?
No, it means you tax only the true investment gain after inflation has been accounted for.
For example, consider the following scenarios:
(1) Wall Street trader Harry Balls buys 100 shares of a hot technology stock for $100,000, and sells it exactly one year + one day later for $125,000.
(2) Blue Collar worker Joe Blow buys a $100,000 fixer-up home for himself and his family to live in. Twenty years later, with the kids having moved off to college and Joe sells the house for $125,000 and uses the proceeds to buy a house closer to his grandchildren.
In these scenarios, both Harry and Joe have a $25,000 capital gain they need to pay an taxes on (sale price of $125,000 less the cost basis of $100,000). Each stroke a $3,750 check to the IRS ($25,000 x .15 = $3,750) based on current rates on capital gains.
However, you've not accounted for the inflationary effects on their respective "investments". Joe's house didn't have that much of a true gain in value, rather inflation caused housing prices to go up in general. To buy the same house Joe paid $100k for 20 years ago, someone now needs to pay $120k today (the replacement cost of his house). Therefore the true investment gain on the property isn't $25,000, it's $5,000 since that accurately accounts for and excludes the last 20 years of inflation.
We've been accounting for inflation via an artificially low 15% rate for years. However, taxing people on "capital gains" that don't exist in reality once you account for inflation is stupid policy on its face. It distorts the incentives to hold investments for the long term, and disadvantages the "little guys" who aren't picking and selling investments on how they can minimize the tax impacts while minimizing the effects of inflation on their gain.
Thus my proposal to tax the true, inflation adjusted gain of an investment at normal income rates, rather than the non-inflation adjusted "gain" at the lower 15% rate.