How to convince the IRS we shouldn't pay 'self-employment' tax

It isn't voluntary if you're paid. It sounds like the Bar treated her as an independent contractor, so she is responsible for her own witholding, including self-employment.

Being "self-employed" may not be so bad. If there were expenses (such as mileage, postage, education, etc.) connected to the self-employment, those expenses may be deductible, reducing the amount of taxes. If the expenses are more than the incomes, there may be a loss that reduces other incomes.

Self-employment taxes replace the Social Security and Medicare taxes paid by employees and employer. There is an annual limit on the portion for Social Security taxes. If the wife is making above the maximum wage subject to Social Security taxes (about $96,000) in her other job, she would not have to pay that portion of the self-employment taxes.

There is a deduction for the portion of the self-employment taxes that would have been paid by the employer.

If she has political aspirations, being too aggressive with finding ways to reduce taxes may not look good.

She may want to review her facts and options with a tax professional.