President Donald Trump's administration has succeeded in gutting the the Affordable Care Act and attacking access to healthcare coverage for low-income families—causing the number of uninsured children in the U.S. to climb to more than four million, a study released Tuesday finds.

The Georgetown University Center study found 400,000 children lost their health coverage between 2016 and 2018, making this year the second in a row to see the number of uninsured children rise.

There are now more uninsured children in the U.S. since the Affordable Care Act (ACA) was enacted in 2014. The Georgetown researchers described the increase as part of "a very troubling trend."

"This is another reason we need Medicare for All—the wealthiest country in the history of the world and our healthcare system can't cover children."
—Ted Terry, mayor of Clarkston, Ga.

"The decline in health coverage occurred at a time when children should have been gaining coverage in the private market and is a red flag for policymakers as even more children would likely lose coverage in an economic downturn," said Joan Alker, executive director of the Center.

Alker blamed the decline on "the Trump administration's actions or inactions that have made health coverage harder to access," including the shortening of the ACA enrollment period; fewer resources given to ACA outreach efforts; a delay in implementing CHIP, which covers families that don't have employer-based insurance and don't qualify for Medicaid; and Trump's "public charge" rule, which experts say has deterred immigrant families for applying for government programs.

The uninsured rate among children dropped sharply after the ACA, also known as Obamacare, went into effect. In 2015, four million children had no health coverage, compared with nearly five million in 2014. Georgetown's study reveals that many of the gains made under the Obama administration have been erased by Trump.

Low- to middle-income families have been hit hardest by the decline in health coverage, and the majority of uninsured children are eligible for Medicaid or CHIP but are not enrolled.

Sen. Ron Wyden (D-Ore.) and Rep. Frank Pallone (D-N.J.) sent a letter to Health and Human Services Secretary Alexander Azar on Tuesday, demanding records regarding the health coverage decline and slamming the Trump administration for claiming, as Medicaid administrator Seema Verma has, that the trend is due to low unemployment rates and reduced reliance on government-funded programs.

"This is a disturbing trend that the administration should be looking to correct, but instead, your administration has applauded the enrollment declines among children," wrote Wyden and Pallone. "And while you assert that they are the result of an improving economy, that is simply not borne out by the evidence."

"If children were leaving Medicaid and CHIP and finding coverage elsewhere, then the number and percent of uninsured children would go down," they added.

Ted Terry, the progressive mayor of Clarkston, Georgia, who is running for a Senate seat in 2020, tweeted that Georgetown's study offers "another reason we need Medicare for All."

"The wealthiest country in the history of the world and our healthcare system can't cover children," Terry wrote. "This election is about the moral character of our nation."