Sen. BernieSanders says the ability of Aetna to disrupt thepublic health insurance exchange system in 2017 by withdrawing from11 states' programs shows why letting private companies sell healthinsurance is a bad idea.

The Vermont independent cited the Aetna exchange move in anannouncement that he will introduce a new "Medicare-for-all" bill in thenext Congress.

Aetna announced Tuesday thatit intends to sell individual coverage outside of the AffordableCare Act exchange system in many markets next year, but to sellindividual coverage through the ACA exchange system only inDelaware, Iowa, Nebraska and Virginia. The Hartford,Connecticut-based insurer said it has to reduce its use of theindividual exchange system because of heavy losses on the sale ofexchange plans.

On Twitter, Sanders linked to an article which quotes from what appears tobe a letter that Aetna sent to the U.S. Department of Justice inJuly. In the letter, Aetna says a Justice Department effort toblock its pending acquisition of Louisville, Kentucky-based Humanaon antitrust grounds would hurt Aetna's ability to support the ACAexchange system.

Indianapolis-based Anthem included a similar point in afull-page ad it put in many national newspapers in July.

Sanders said in a statement that it is disappointing to see thatAetna has joined other large for-profit health insurance companiesin pulling out of the ACA exchange system. "

"Despite the Affordable Care Act bringing them millions morepaying customers than ever before, these companies are moreconcerned with making huge profits than ensuring access to healthcare for all Americans," Sanders said in the statement.

"In my view, the provision of health care cannot continue to bedependent upon the whims and market projections of large privateinsurance companies whose only goal is to make as much profit aspossible," Sanders said. "That is why we need to join every othermajor country on earth and guarantee health care to all as a right,not a privilege. That is also why we need to pass aMedicare-for-all single-payer system. I will reintroducelegislation to do that in the next session of Congress, hopefullyas part of the Democratic Senate majority."

The next Congress is set to start in January 2017.

Sanders' past American Health Security Act bills would lethealth care providers collect reimbursement only from state-runhealth plans, not from patients or private insurers. (Image:Thinkstock)

How Sanders' single-payer plan might work

Advocates of a "public option" program want the government torun a public health insurance program for working-age people thatoperates alongside commercial health insurance plans.

In a pure single-payer system, a government health insuranceprogram acts as the sole source of health coverage.

Sanders argued in 2010 that offering universalaccess to a public coverage option would be better than thesystem that was in place in 2010. But, when Sanders has introducedhis own American Health Security Act bills, he has supported movingthe country to a pure single-payer system.

In Sanders' American Health Security Act bills, he has proposedthat each state should have its own publicly funded health plan andhealth plan board.

Each state's plan would pay for all medically necessary acutemedical care and long-term care.

A state's health plan board would negotiate reimbursement rateswith the state's health care providers.

Providers could collect payments only from the state plans, notfrom the patients or private insurers.

If a state's health plan started to run out of cash, the planwould balance its books by cutting its provider reimbursement rateuntil the start of the next fiscal year.