For the past several years, House Budget Committee Chairman Paul Ryan has complained that the U.S. economy has been growing at too slow a rate.

Now, as unemployment rates drop and job creation seems finally to be accelerating, Ryan is suddenly fretting about the prospect that the economy might grow too quickly.

Why?

The answer has nothing to do with economics and everything to do with politics.

Despite the steady opposition of Ryan and other leaders of the Republican-controlled House, the Obama administration can now point to a pattern of monthly decreases in the unemployment rate. While the administration’s response to the unemployment crisis of the past three years was less than it should have been, a combination of stimulus policies and investments, as well as the determination of the Federal Reserve to keep interest rates low, appears to be working. For the fifth straight month, unemployment has fallen. The rate now stands at 8.3 percent — down from 10 percent in October 2009.

The official unemployment rate is now at the lowest point since the first months of Barack Obama’s presidency.

But it is the pattern of decrease that matters politically.