Are you a sinner?

Do “sin taxes” on items like cigarettes and sugary drinks really work to curb bad habits?

In his first address to a joint session of Congress on Tuesday, President Donald J. Trump promised “massive tax relief for the middle class.” At the same time, state and local governments are scrambling for new sources of revenue to plug growing budget holes.

Increasingly, cities and states are turning to “sin taxes” as funding sources. By levying an increased cost on disfavored activities — things like gambling, alcohol, smoking and, increasingly, soda consumption — legislators can find new dollars for a variety of needs.

Here in Oklahoma, Gov. Mary Fallin has proposed to boost state revenues by increasing the cigarette tax by $1.50 a pack. Last Month, the House Appropriations and Budget Committee voted to advance the bill, which is projected to generate additional annual revenues of more than $250 million.

“A tax on tobacco is probably the easiest revenue-raising proposal that you can pass,” said House Speaker Rep. Charles McCall, R-Atoka. That’s because such taxes are also seen to serve a second purpose: curbing the behavior that they tax.

But do taxes really impact behavior?

In 2014, a study by the surgeon general’s office looked at this question. The research found that cigarette taxes do deter smoking. And their effectiveness tied directly to how hard they hit smokers’ pocketbooks.

For every 10 percent increase in the cost of cigarettes, the surgeon general determined that smoking rates go down four percent. If the full House and Senate pass Gov. Fallin’s proposal, the average cost of a pack of cigarettes in Oklahoma will climb from about $6.50 to $8, a jump of roughly 25 percent.

That 25 percent increase would translate to a 10 percent drop in smoking from our current levels. According to the director of the Center for Tobacco Control and Education, the decline in smoking rates following tax increases falls into two buckets: “Part of that is people quitting. Part of that is people cutting down.”

In other words, folks know that smoking is bad for them. They generally want to quit the habit. Still, the craving for a cigarette at the moment can overwhelm the fear of health consequences in the future.

However, a new disincentive at the time of purchase — added cost — can reverse the equation for some. For others, it may not stop the transaction altogether. But it may lead them to slow their consumption so that they don’t need to make another expensive purchase quite so soon.

Either way, it’s a win for health.

Sinful sodas

Soda taxes are the newest front in the sin tax battle. Philadelphia, San Francisco and the county that contains Chicago have all recently passed taxes on sugary drinks, joining a growing list of communities that discourage their citizens from having a Coke and a smile.

With America — and the world — now caught in a diabetes and obesity epidemic, curbing sugar consumption has become a public health priority. While the public long turned its nose up at soda taxes as “nanny state” proposals, sentiment seems to have flipped when new tax dollars are dedicated for use in much-needed areas like public education (as they are in Philadelphia).

Soda taxes generally add a penny or two an ounce to the cost of a sugary drink. They’re too new for research studies yet to assess their longterm effectiveness in decreasing consumption of sweet drinks. But a case study from Mexico offers some early clues.

In 2014, Mexico passed a tax on all beverages that contained added sugar, including carbonated soft drinks, fruit drinks and sweet tea. At a tax rate of 10 percent, it’s considerably lower than the U.S. soda taxes. (For a sixpack in the U.S., you’d see taxes ranging from 70 cents to a bit over a dollar, while in Mexico the tax would be roughly half that amount.)

After Mexico’s soda tax took effect in 2014, sugary drink sales fell by 5.5 percent compared with the year before. The biggest decreases were among low-income Mexicans.

Some industry analysts and anti-tax advocates argued that the one-year results might prove to be an aberration, wiped away when consumers adjusted to higher prices. But a new study published last month showed just the opposite: In 2015, Mexicans cut their soda intake even further, with consumption levels dropping almost 10 percent from 2013. Again, the poorest people cut back the most.

In the U.S., I’d expect to see similar results. The tax will deter purchases, and over the long haul, significant portions of the population will change their habits and decrease or eliminate their consumption of sugary beverages. If anything, I’d expect the effect to be more profound here, as our soda taxes are stiffer than Mexico’s.

Whether reducing soda consumption results in a drop in obesity and diabetes rates will take years to determine. But one thing is already clear: If you want to change consumers’ behavior, taxes work.