In retrospect, it seems odd that so many business analysts expected the U.S. Department of Justice to approve the proposed mergers of four enormous health insurers.

From the time the proposed deals were announced last year, consumer advocates and Democratic politicians weren't warm to Aetna's plans to acquire Humana or Anthem's plans to buy Cigna. The acquisitions, if approved, would shrink the number of large health insurers in the country from five to three.

While many on the left have accused the Obama administration of coddling insurance companies, most notably by enshrining their role in the health care system through the Affordable Care Act, the president and his allies have also been vehement that the insurance business needs strong governmental oversight.