No, you can’t relax about Obamacare yet.

The big Affordable Care Act number of the week is 11.4 million — that’s the number of people who enrolled in 2015 health insurance plans through the law’s marketplaces, according to a White House announcement Tuesday. The total is 2.3 million higher than the goal the administration set at the outset of this open enrollment season. “It’s working a little better than we anticipated,” President Obama said of the ACA phase in.

Let’s not get too carried away: The news is good, but not awesome. The law is finding its footing. But the enrollment number will decline. Some people counted in that 11.4 million, for example, will skip out on their monthly payments. More than a million people left ACA marketplace insurance plans after open enrollment last year. The number of people covered in ACA marketplaces will probably settle well below the 12 million that the independent Congressional Budget Office projected for 2015 enrollment.

Besides, the government should still be signing people up, rather than shutting down open enrollment. The deadline to buy health insurance passed before tax season ended this year, and a lot of uninsured people will be hit with tax penalties for the first time when they sit down to finish their 1040’s. Federal overseers should extend open enrollment into April this year to give those people a break, then see where total enrollment ends up after that.

But these issues are tiny compared to the implications of another Obamacare number the government released recently: 6.5 million. That’s the number of HealthCare.gov customers who, as of Feb. 9, the Health and Human Services Department reckons will be due government help in paying their insurance premiums. The number will rise significantly as HHS adds data from this month’s brisk enrollment. For now, HHS estimates the average benefit to be $268 per person per month, enabling some 80 percent of HealthCare.gov users to buy health plans for $100 or less per month out of pocket. This assistance could vanish with a hostile Supreme Court ruling this year.

Revoking this aid would deal a devastating blow to insurance markets that, as this week’s 11.4 million enrollment figure indicates, are just establishing themselves. The Urban Institute has already gamed out the results: Healthy people would drop coverage, raising costs for the sicker people who stay in the insurance system. The number of uninsured would go up, insurance premiums would go up, the quality of insurance that people had would decline, and the law’s finely tuned marketplaces would teeter near collapse.

In other words, Obamacare’s good news is purely conditional until the justices rule, probably in June. You can go back to holding your breath now.

UPDATE, 12:30 p.m.: Text above slightly edited for clarity.