Bernie Sanders formalized the Democratic Party’s left turn on Tuesday, finally endorsing Hillary Clinton and praising her for embracing so many of his ideas. “We have begun a political revolution to transform America, and that revolution continues,” the Vermont socialist said—and the latest evidence for his boast is the revival of ObamaCare’s “public option.”

This liberal ambition—a new health-care entitlement akin to Medicare for all middle-class Americans under age 65—couldn’t pass a Democratic Congress in 2010. Mrs. Clinton revived the public option over the weekend, and now President Obama is also lending his support, in an op-ed that appears under his byline in this week’s Journal of the American Medical Association.

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The battle between congressional Republicans and the White House over the Affordable Care Act is again escalating—in court and on Capitol Hill.

The administration on Wednesday appealed a federal trial judge’s ruling that the government is improperly reimbursing insurers under a program to cover discounts for low-income consumers.

And House Republicans on Thursday began two days of hearings to hammer away at the issue. They released a report that said the administration distributed the funds even though it was aware it needed Congress’s approval.

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The Republican House is methodically laying out a comprehensive agenda to spread prosperity, protect the nation, uphold the Constitution, reform health care, and—with its presentation Friday of a comprehensive tax-reform plan—create jobs, grow paychecks and boost the economy.

This agenda, dubbed “A Better Way: Our Vision for a Confident America,” is Speaker Paul Ryan’s brainchild, but the work of the entire Republican conference.

Mr. Ryan rolled out its first plank June 7 with an audacious reimagining of policies to help Americans rise out of poverty. The initiative would require those on welfare to seek work while providing them better access to job training and assistance. It would reform poverty-fighting programs to help people move from dependency on government to lives of independence and personal responsibility.

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A House Republican alternative to Obamacare is coming this week, and some reports suggest it will include a refundable tax credit to subsidize health insurance. This would present some tough political and policy choices about whether and how to pay for a new program of tax credits.

Changing the tax treatment of employer-provided health insurance could provide one of the largest potential sources of financing for a new refundable credit. It also would bring hefty trade-offs. On the political side, capping the deductibility of employer-based health plans to finance refundable credits that are considered government spending would not please some Republicans. Put another way: Repealing Obamacare’s tax increases to replace them with other revenue increases is unlikely to go over well with conservative voters.

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Maryland’s health cooperative filed a lawsuit Monday seeking to block the federal government from requiring it to pay more than $22 million in fees for a program designed to cover insurance company shortfalls.

The lawsuit by Evergreen Health Cooperative Inc. is the latest twist in the saga of health insurance co-ops set up under the Affordable Care Act to compete against larger, established insurers.

The co-ops were supposed to help keep premiums down by injecting competition into the industry. Instead, 13 of 23 startups that launched successfully have since collapsed, forcing more than 700,000 consumers to seek new insurance. A number of co-op officials have said they were hurt by the federal program because of a formula it used to spread out risk, which they say hurts them while benefiting large, already established insurance companies.

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The Obama administration is seeking to limit short-term health policies that include features largely banned under the Affordable Care Act, a proposal that could crimp a profitable and growing business for some insurers.

Under a proposed rule released Wednesday, insurers would only be able to offer short-term health policies that last less than three months, and the coverage couldn’t be renewed at the end of that period. The proposal seeks to close a gap that has let healthier consumers purchase short-term plans that could last for nearly a year, sometimes using them as a cheaper substitute for ACA plans.

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Blue Cross and Blue Shield of North Carolina sued the federal government, becoming the latest health insurer to claim it is owed money under the Affordable Care Act.

The suit, filed on Thursday in the U.S. Court of Federal Claims in Washington, D.C., says the U.S. failed to live up to obligation to pay the insurer more than $147 million owed under an ACA program known as “risk corridors,” which aimed to limit the financial risks borne by insurers entering the new health-law markets.

The suit argues that the federal government violated the language of the health law, as well as a contractual obligation to the North Carolina insurer.

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Republican lawmakers crafting alternatives to Obamacare face a fundamental decision: whether to focus on expanding coverage or containing costs. Their choice may be driven, at least in part, by budget scorekeepers.

The Congressional Budget Office released a report in December 2008 on key issues in analyzing major health-care proposals. Included was a chart projecting individuals’ willingness to enroll in health insurance at various levels of subsidy (in technical terms, an elasticity curve). That curve suggested that insurance enrollment would remain below 40% until subsidies reached 70% of cost and that even if costs were 100% subsidized, about a fifth of individuals would decline to enroll. (And that level of subsidy is probably much greater than many Republicans would be willing to offer.)

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Will ObamaCare be a top issue in this fall’s presidential and congressional campaigns? Republicans better make it one if they want to prevail.

The continuing unpopularity of President Obama’s signature domestic achievement gives Republicans an enormous opportunity. Only 39.2% of Americans favor ObamaCare in the Real Clear Politics average of recent polls; nearly half, 48.8%, oppose it. There’s also a sharp partisan divide that benefits the GOP: While 78% of Democrats approve of ObamaCare, according to an April survey from the Pew Research Center, 58% of independents and 89% of Republicans disapprove of it.

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A federal district judge ruled this month, in a lawsuit brought by House Republicans, that the Obama administration lacks the authority to pay cost-sharing subsidies to health insurers if Congress has not appropriated the funds. Some civil servants in the administration may agree.

The House Ways and Means Committee released a deposition Tuesday of David Fisher, former chief risk officer for the Internal Revenue Service. In it, Mr. Fisher recounts a series of events in late 2013 and early 2014 regarding the source and legality of Obamacare cost-sharing subsidies to insurers.

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