Republicans and their allies are still insisting that a key Obamacare provision amounts to a taxpayer-funded “bailout” of the insurance industry. And now they may demand its repeal in exchange for giving the U.S. Treasury authority to borrow money and pay the government’s bills.

The provision is called the “risk corridor” program. And while it’s unclear whether Republicans are really willing to have another showdown over the debt ceiling, it’s clear they intend to keep making the “bailout” argument—right up through the midterm elections. “The idea that the federal government should be bailing out insurance companies in order to make Obamacare work, that’s not something a lot of people are aware of,” Senator Marco Rubio said on Fox News a week ago. “I haven’t taken a poll on it, but I guarantee you it would be hugely unpopular.”

Rubio is probably right about the politics. But the substantive argument Republicans and their allies are making remains unconvincing—for some reasons that are familiar and one that may not be.

To review, in case you missed the discussion earlier this month: The risk corridor program is one of the law’s built-in “shock absorbers,” designed to stabilize the insurance market while carriers adjust to new regulations that prohibit them from denying coverage, withholding benefits, or charging higher premiums to people with pre-existing medical conditions. The rationale for these provisions is pretty simple.

Insurance companies set premiums based on who is likely to buy their insurance policies. But, particularly when a new program is starting, the company actuaries can’t make such predictions with a lot of confidence. An insurer might guess wrong—by, for example, underestimating how many young, healthy people will buy. If that happens, the premiums won't be sufficient to cover medical bills, and the insurer will lose money. The opposite can also happen. An insurer might expect to attract lots of sick people, but end up with only a few. In that case, the insurer would have more than enough money to pay medical claims—and end up with a windfall.