Indulge me here. Let’s say I am long 1000 PM in my Roth IRA and then short 1000 in a different account, fully taxable, with a different broker. Hold both. My Roth dividends are not going to be taxed. But I can still deduct the dividends I pay in my short account, giving me a net gain, a slight one, but a riskless one. Correct? What would the IRS say?