To opponents of the Affordable Care Act, Aetna’s recent announcement that it will withdraw from all but four ACA marketplaces is more evidence that the landmark health law is doomed to fail.

But, as BenefitsPRO pointed out two weeks ago and Democrats are pointing out now, the timing of Aetna’s announcement strongly suggested that the move was as much about political gamesmanship as business.

Aetna’s decision to dramatically reduce its participation in the ACA marketplace came shortly after the Obama administration announced it would seek to block Aetna’s bid to acquire rival insurer Humana, along with another insurance megamerger between Anthem and Cigna.

Until that point, Aetna had projected confidence about the future of its Obamacare business, saying not only that it was committed to remaining in the marketplace and that it was planning to expand its presence.

On Wednesday, the Huffington Post made public a letter from Aetna CEO Mark Bertolini to the U.S. Department of Justice in which company representatives said it would pull out of the ACA marketplace if their desired merger was blocked. If the deal was not approved, “instead of expanding to 20 states next year, we would reduce our presence to no more than 10 states,” the letter said.

The letter went on to justify the apparent threat as the result of simple economics. Unless it could absorb one of its largest rivals, Aetna contended, it would not be in a strong enough place financially to expand its ACA business.

“Our customers expect us to keep their insurance products affordable and continually improving, and our shareholders expect that we will generate a market return on invested capital for them,” explained the letter.

ACA supporters aren’t buying it.

“Aetna’s CEO had touted the ACA marketplace as a good investment in April, which raises very serious concerns about Aetna’s sudden change of heart,” Rep. Frank Pallone, D-N.J., told Politico.

Sen. Elizabeth Warren, D-Mass., also expressed outrage in a Facebook post.

“The health of the American people should not be used as bargaining chips to force the government to bend to one giant company’s will,” she said.

Humana, the other party of the proposed Aetna merger, has also announced a major reduction in its marketplace plans. UnitedHealth, the nation’s largest insurer, was the first to make such a move, pulling out of all but several states next year.