Washington — "Junk insurance," as Democrats call it, isn't going anywhere. A resolution to overturn President Trump's rule that allows states to sell plans that violate Obamacare failed in the Senate on Wednesday.

The Affordable Care Act (ACA), President Obama's signature legislation, requires health insurers to grant coverage to people with preexisting conditions and cover certain "essential benefits" like mental health and prenatal care. Under Mr. Trump's changes, those rules can be waived, and federal subsidies can be used to help people buy these leaner, cheaper plans.

The resolution, which was introduced by Senate Minority Leader Charles Schumer, needed a simple majority to pass. It failed 43-52, with one Republican, Susan Collins of Maine, supporting it.

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The vote comes at a time when the fate of Obamacare is uncertain.

A federal court is expected to rule soon on whether the ACA is unconstitutional. The lawsuit was brought by Republican state attorneys general and is supported by the Trump administration, even though the executive branch typically defends federal laws in court.

The legal precariousness has led to fears about whether people with preexisting conditions will be able to buy health insurance if the law is struck down. The Trump administration hasn't done much to alleviate those fears.

In a tense congressional hearing last week, Seema Verma, the administrator of the Centers for Medicare and Medicaid Services, spent hours dodging questions about what the contingency plan is if Obamacare isn't upheld. It was her first time appearing before a Democratic-led House committee.

At one point, Verma argued that people don't really have protections for preexisting conditions as it stands, because they can't afford to buy health insurance in the first place. Her comments follow reports that Obamacare premiums are expected to drop next year, for the second year in a row.

The ACA led to a historic high number of Americans, including children, having health insurance. But under Mr. Trump — who pledged to repeal Obamacare — that trend has reversed. In 2018, for the first time in 10 years, the number of uninsured Americans increased, according to a Census Bureau report in September. A report released on Wednesday by the Georgetown University Center for Children and Families shows the number of children who lack health care increased last year for the second year in a row.

Since Mr. Trump took office, his administration and Republicans in Congress have made a series of changes that undermine the law, such as repealing the individual mandate that required people to have health insurance, limiting the amount of time people who have to sign up for health care, drastically cutting the budget for Obamacare outreach and allowing states to enact work requirements as a condition of Medicaid eligibility.