|Governor Sam Brownback|
Laffer's curve is laughable for a number of reasons but the most obvious is the simple algebra it depends on.
Assume Kansas has GDP of $100 billion. (And that's not far off. The state's GDP is about $117 billion according to Google.) With a tax rate of 6.25%, that gives the state income tax revenue of $6.25 billion.
Now, cut the tax rate to 4.9%. In order to maintain tax revenues at $6.25 billion, total GDP would have to raise to $127.5 billion. In other words, it would have to grow by 27% to offset this tax cut. To put that in perspective, the US economy will probably grow about 2.5 to 4% this year. China's economy will grow about 7 to 8%, Europe's closer to 0%. 27% would be an absolutely stunning, unprecedented rate of growth. Even during a full, four-year term. And all triggered by the magic of dropping marginal tax rates from 6.25% to 4.9%, a tax cut that (Laffer would argue) would finally give people the incentive to get rich.
If Brownback knew algebra, he could have quickly calculated the growth rate he'd need to balance the budget with his new tax rate. Sadly for the state, that level of math competency was apparently not needed to qualify for the governor's job.
I suspect that Brownback will win re-election but a couple of interesting articles suggesting he might not can be found here.
Mother Jones, Patrick Caldwell, "What's the Matter With Sam Brownback?"
The New Republic, John B. Judis, "This is What's the Matter With Kansas"