People who ask about my decision to line-item-veto the Minnesota House and Senate's appropriations are mostly concerned about what I did. The more important question is: Why did I do it?

I don't want to permanently defund the House and Senate. I'm not engaging in some petty retaliation for the Legislature's last-minute shenanigans.

What I am doing is defending the integrity of the state of Minnesota: Our state's financial integrity, the integrity of our state's professional teaching standards and the integrity of the way decent Minnesotans must treat other decent Minnesotans if we are all to succeed together.

When I became governor in January 2011, our state government faced a projected $6.2 billion budget deficit in the upcoming biennium. Since then, we have worked very hard to restore Minnesota's fiscal integrity. We turned the state budgets from chronic deficits to consistent surpluses. We repaid more than $2 billion the state had unilaterally "borrowed" from our school districts. We eliminated other payment shifts and accounting gimmicks that had previously been used to disguise those deficits. We finally succeeded: The last eight state financial forecasts have projected budget surpluses.

Most Republican legislators opposed the tax reform most responsible for reversing our state's fiscal misfortunes. In 2013, we increased the state's income tax rate on the wealthiest Minnesotans. That 2 percent rate increase on the top 2 percent, along with the increase in cigarette taxes and the state's growing economy, have provided us with additional revenue and an estimated budget surplus of $1.65 billion this year.

Some of them repeat the falsehood that I have raised state income taxes on all Minnesotans, which are to blame for those surpluses; therefore, they argue that it all should be "given back."

That is untrue, and they know it. Our state's income tax rates have remained the same for 98 percent of Minnesotans since 2000.

But their tax bill doesn't give it back to everyone. Instead, its benefits are wrongly weighted to their favored friends: the rich and powerful. They increased the estate tax exemption for about 1,000 Minnesotans from $2 million to $3 million, at a cost of $109 million over the next four years. They gave special tax breaks to Big Tobacco, totaling $53.2 million in the next two biennia. Most incredibly, they even provided a special tax break for premium cigars.

After these and other excesses, the total cost of their tax bill will greatly jeopardize our state's financial security in years ahead. The Minnesota Department of Revenue estimates that the bill will reduce state revenue by $5.1 billion over the next 10 years.

The Department of Management and Budget says that even a moderate recession would likely cause a $2.1 billion reduction in state revenue in the following 12 months. In the likelihood of even a moderate national recession sometime during the next decade, that $5 billion in lost revenue could be the difference between a fiscal challenge and a crisis.

The Legislature's other bills contain a number of wrongheaded policies. Two, however, stand out as unacceptably destructive to our state's social cohesion.

In one, a majority of legislators insisted upon adding redundant and, therefore, completely unnecessary language repeating a prohibition that undocumented immigrants cannot obtain Minnesota driver's licenses.

I was in the U.S. Senate in 2001 when the comprehensive immigration reform agreement between President George W. Bush and Senate Majority Leader Tom Daschle collapsed in the aftermath of 9/11. Since then, sensible reform initiatives have been paralyzed, leaving thousands of undocumented Minnesotans in a legal Twilight Zone.

Many of them have lived in this country for many years, and most are hardworking, responsible people. They are indispensable employees for many Minnesota companies, and they are part of an increased immigrant labor force that is essential to our state's continued economic growth.

Common sense should tell us that everyone driving on our streets and highways would be safer if everyone else had to take driver education, pass a road test and have proper insurance.

Nevertheless, a majority of legislators decided that it would be politically advantageous for them to restate this prohibition, thus pandering to those Minnesotans who still harbor anti-immigrant prejudices.

They must believe that this poke in immigrants' eyes somehow gains them political advantage with those constituents. However, it is unnecessarily divisive and destructive to the social cohesion upon which we all depend.

The other nontax provision is a major change in Minnesota's teacher licensure system. I support some of those changes. The problem comes when the law permits people who have not earned education degrees to become permanent teachers.

Many national tests and evaluations have shown that Minnesota has one of the best public education systems in the country. The best education starts with the best educators. Every student deserves teachers who have been trained and tested to possess the sophisticated skills they need to be effective in today's classrooms.

Current speculation centers around whether House and Senate leaders will take legal action to try to overturn my decision. That tactic allows them to avoid addressing these vital issues, which I have raised. The people of Minnesota would be far better served if, rather than preparing legal briefs, those legislative leaders would instead brief their fellow citizens on why they are unwilling to reverse actions that will be so detrimental to our shared future.

Mark Dayton is governor of Minnesota.