Oh dear. The Republican Party’s worst nightmare is coming true. Obamacare is working.

The news that nearly 1.2 million people signed up last month for insurance through the Affordable Care Act exchanges is highly inconvenient for GOP candidates nationwide. It looks as if the party’s two-word strategy for the fall election — bash Obamacare — will need to be revised.

Wednesday’s status report on the health-insurance reforms was by far the best news for Democrats and the Obama administration since the program’s incompetent launch. January was the first month when new enrollments surpassed expectations, as the balky HealthCare.gov Web site began functioning more or less as intended.

Cumulatively, 3.3 million people had chosen insurance plans through the state and federal exchanges by the end of January. That is fewer than the administration had originally hoped but well above the predictions of critics who believed — or hoped — that the program would never succeed. The Congressional Budget Office projects that 6 million people will have chosen plans through Obamacare when the initial enrollment period ends March 31, down from a pre-launch estimate of 7 million. Not bad at all.

The numbers are even more encouraging when you look more closely. The proportion of young people — from 18 and 34 — who chose insurance plans through the exchanges increased slightly to 27 percent, compared with an average of 24 percent in previous months. This is important because premiums would have to rise if not enough young, healthy people enrolled.

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The administration had hoped the percentage of young enrollees would reach about 40 percent. But the January figure — and the rising trend — should put to rest any notion that the whole program could go down the drain in an actuarial “death spiral.” Administration officials are convinced this won’t happen.

According to the January report, about 80 percent of those signing up for Obamacare are eligible for subsidies to help them pay for insurance. The administration believes, but does not have the data to prove, that most of the new enrollees were previously uninsured.

These figures do not include the additional people who have been determined newly eligible for insurance under the federal-state Medicaid program. Overall, the program appears to be doing exactly what it was designed to do: make health insurance accessible and affordable for those who truly need it.

The Affordable Care Act could be doing even more if Republican governors such as Rick Perry of Texas and Rick Scott of Florida were not doing all they could to sabotage the program. But even in states that refused to set up their own health-insurance exchanges or to expand Medicaid eligibility, growing numbers of the uninsured are obtaining coverage.

Politically, this is terrible news for Republicans who hoped that the botched Web site launch and President Obama’s misleading “you can keep your insurance” pledge would be the gifts that kept on giving.

Bashing Obamacare will always have resonance for the GOP’s conservative base. But if you’re trying to win the votes of independents, it’s more profitable to target a failed program than a successful one.

Critics will doubtless try to blame Obamacare for anything bad that happens to anyone’s health insurance before the November election. But all of this is just noise without the central narrative of a “failed program.”

Attack ads against vulnerable Democratic senators, such as Kay Hagan of North Carolina and Mary Landrieu of Louisiana, are already trying to paint Obamacare as a character defect — the president and his supporters “lied” when they said everyone could keep their insurance. The response from Democrats should be to shift the focus to the actual program and its impact. Imperiled incumbents can point to constituents who are benefiting from the Affordable Care Act in life-changing ways.

If you assume that Affordable Care Act enrollment remains on its current trajectory, the February numbers should look even better. Polls consistently show that even if voters have mixed views about the health-care reforms, most do not want to see them repealed. By the fall, the whole Obamacare-is-a-disaster line of attack could sound stale and irrelevant.

Republicans may even have to take the drastic step of saying what they advocate, rather than harping on what they oppose. Is there a GOP plan to cover those with preexisting conditions? To cover the working poor? Is expanding access to health insurance really such an awful thing?

Sorry, I didn’t catch what you said.

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