After claims from insurance companies that they plan to dramatically increase premiums this year because of the Affordable Care Act, the White House fired off a threat to the industry’s main lobbying group today.

Writing to the head of America’s Health Insurance Plans, Health and Human Services Secretary Kathleen Sebelius said insurers that hike rates for consumer unjustifiably may be locked out from the state exchanges due to be set up by 2014. These exchanges will be the primary means by which small groups and individuals will purchase coverage. Being excluded from these marketplaces could be devastating to insurers. (full text of the letter after the jump)

The overt nature of Sebelius’s warning shot means a few things. It means that HHS knows that the industry’s support during the health care reform debate means little now. And it means that HHS is tough – ready and willing to use all means necessary to stop insurers from padding profits and using the Affordable Care Act as an excuse. It’s this second matter that’s worth more exploration.