Whether a capital gains income tax is constitutional is one issue; whether it would end with that is another. Capital gains income tax revenue is highly volatile, as are other taxes aimed at the wealthy. When the economy goes into a downturn, lawmakers will be left to scramble for new sources of money, as has been seen in other states. A broader income tax likely would not be far behind.

The experiences of California and Connecticut demonstrate the point. The severe downturn of 2008-2009 was especially difficult for California, where capital gains rates are highest in the nation and income tax brackets are skewed heavily toward the rich. Tax collections fell dramatically, and the state was forced to compensate by  raising taxes on the middle class. A newly disclosed half-billion-dollar deficit in Connecticut is directly related to its capital gains income taxes — and lawmakers there already are talking about imposing higher income taxes on the general population.

At a news conference May 13, 2016, California Gov. Jerry Brown explains that reliance on unpredictable capital gains taxes has created major problems for his state.


WTNH-TV (New Haven, Conn.), April 28, 2017: Income tax revenue collapses; Malloy says taxing the rich doesn’t work

“Next year’s deficit has ballooned to $2.2 billion. It’s happening because the state of Connecticut depends too much on its wealthy residents, and wealthy residents are leaving, and the ones that are staying are making less, or are not taking their profits from the stock market until they see what happens in Washington. …It now looks like expected revenue from the final income [tax] filing will be a whopping $450 million less than expected.”


New Haven Register, May 1, 2017: Drop in income tax receipts plunge Connecticut’s budget further into deficit

“Personal income tax revenues were down $450 million from projections. More specifically, a majority of the decline in income tax receipts is from the withholding and finals portion of the tax. which is tied to capital gains and investment income. That part ended up being down 8.9 percent.”


Connecticut Mirror, May 2, 2017: House speaker: Deficit too great to rule out income tax hike

Connecticut’s Democrat-controlled legislature is now looking for ways to replace the lost revenue. One likely option — increases in the income taxes paid by the middle class. ” ‘As the hole in the budget grows, the options become more limited,’ [House Speaker Joe] Aresimowicz said. With that in mind, the speaker added, he couldn’t rule out income tax hikes on the wealthy or on the middle class at this point.”


The (Tacoma) News Tribune, April 6, 2017: House Democrats want a capital gains tax to raise money for their budget plan – is it even legal?

“The state Supreme Court has ruled in the past that income taxes are a form of property taxes — which must be applied at a flat rate under the constitution. The capital gains tax measure isn’t uniform because higher earners pay more, Republicans say.”


Jared Walczak, Tax Foundation, in Tri-City Herald, May 12, 2016: Capital gains taxes are too unreliable to fund education

“Large swings in capital gains are not uncommon, making them a particularly risky tax base. Nationwide, they are the single largest culprit behind state revenue forecasting errors. Relying on such a volatile revenue source to boost educational expenditures is risky. A revenue stream that can decline this rapidly is not one that can be relied upon to support meaningful long-term investments in public education.”


Jared Walczak, Tax Foundation, March 24, 2017: A capital gains tax would be more volatile than Washington state revenue projections suggest

Posting notes that simplistic fiscal estimates from the Washington Department of Revenue make no mention of the fact that tax collections would plummet in the next downturn. “There is little one can say with confidence about capital gains tax revenue. The only thing we can be reasonably sure of is that it won’t look anything like this.”


Washington Policy Center, April 2017: State revenue departments describe capital gains income taxes

An exhaustive survey by Jason Mercier of the Washington Policy Center reveals that no other state has a standalone tax on capital gains income – all states that tax capital gains income do so as a component of their state income taxes. None attempt to conceal the purpose by calling it an “excise tax.”


Los Angeles Daily News, Dec. 1, 2016: California budget analysis calls for caution

An editorial in the Los Angeles Daily News observes that heavy reliance on high-earner taxes has created major problems for California. “The [California Legislative Analyst Office] notes that revenues from the personal income tax amount to about 70 percent of the General Fund, and that revenue source is highly dependent on capital gains. …That means California’s state revenue is overly dependent on high tech, and any sizable correction in that sector — even absent a general recession — will send state government tumbling into deficit spending again.”