Aetna CEO Mark Bertolini’s threat that his company would cut participation in the Affordable Care Act’s state insurance exchanges if the Justice Department got in the way of its proposed mega-merger sounded uncomfortably like blackmail. Perhaps a better analogy is the kid who threatens to take his ball home if everyone won’t play by his rules.

In any event, it is good that the Justice Department did not let the foot pounding alter its decision. A month ago, U.S. Attorney General Loretta E. Lynch announced that the government had filed antitrust lawsuits to block the proposed mergers between Aetna and Humana and between Anthem and Cigna.

The move was the right one. The two mergers would have reduced the big five national health insurance providers to three. Reduced competition would have discouraged innovation and substantially abridged the competition necessary to keep the cost of premiums under control and care options attractive.

This action continues a more aggressive and welcomed approach by the Obama administration in its second term to block mergers that may sound good for Wall Street but not for consumers on Main Street. Another recent example was the government’s ability to block the contrived, tax-dodging union of Pfizer and Allergan.

In the wake of the Justice Department’s action, the Bertolini letter has surfaced, released in compliance to a Freedom of Information Act request from the Huffington Post.

In the letter, Bertolini warns Justice that “it is very likely we would need to leave the public exchange business entirely … should our deal ultimately be blocked.”

On the other hand, wrote Bertolini, tossing in the carrot after whacking away with his stick, “if the deal proceeds … we would explore how to devote a portion of the additional synergies … to supporting even more public exchange coverage over the next few years.”

Following through, the company announced earlier this week that it would leave 11 of the 15 exchanges it is participating in and discontinue plans to expand into others.

Strange that only a few months ago, Aetna shared the good news that 1.2 million new customers had signed up with the company through the online exchange markets.

The lesson, in addition to never kowtowing to bullies, is to revisit the public option that would offer helpful competition on the exchanges, an idea abandoned to get the votes needed to pass the law. Aetna, we suspect, will eventually be back.