On June 18, the House, by an overwhelming vote, passed a bill to repeal a tax on the makers of medical devices that was supposed to help fund the health reform law. It has also passed another bill to eliminate an independent board that is supposed to ensure that Medicare spending remains within specified targets, thereby saving the health care system money. The fate of these two bills now lies with the Senate, where Democrats must do their best to prevent veto-proof majorities. There is talk that the Republicans may rely on budget reconciliation processes to pass these measures (allowing them to avoid a filibuster), though it is very unlikely they could overcome a veto by President Obama.

Meanwhile, a prominent lawsuit filed in the name of the House of Representatives is working its way through the courts. It seeks to block the administration’s right to reimburse insurers that provide cost-sharing subsidies for very poor people and to have declared unconstitutional the administration rules that softened the mandate on employers to provide insurance.

In light of these lines of attack, it is imperative that in 2016 voters elect people to Congress and the White House who will support health care reform. It is equally important that as many uninsured people as possible be reached and enrolled in private plans or Medicaid. The greater the number of people who benefit from the health reform law, the harder it will be to dismantle it.

States will have an important role to play in expanding coverage. Some 21 states, the vast majority run by Republican governors, have refused to expand their Medicaid programs to include childless adults and people with higher incomes, as the law allows. The federal government will be paying 100 percent of the cost of expanded benefits this year and next, gradually tapering down to 90 percent in the future. Yet the Republicans, gripped by an irrational hostility to helping the poor, would rather hurt the uninsured and damage their state economies by refusing federal money.

It has long been clear that the Republicans in Congress have no workable plan for replacing the Affordable Care Act, and can’t even fake it. The Republican presidential candidates think they can energize their base with pledges to repeal reform. Though as Mr. Obama said on Thursday, “This is not an abstract thing anymore” but a law that “is now helping tens of millions of Americans.”