(CNN) The Trump administration's decision not to defend key provisions of the Affordable Care Act could deal Democrats a sizable win going into the midterm elections, handing a party already prepared to run on health care a cudgel to use against vulnerable Republicans.

Voters, both in interviews and a series of polls, have consistently said that health care is the issue they care the most about going into the midterm elections and Democratic candidates have responded by making it the cornerstone of their attacks on Republicans.

On Thursday, the Trump administration clearly outlined their position on key -- and popular -- provisions in the Affordable Care Act, telling a court that the law should be invalidated and that the individual mandate is unconstitutional. In the legal filing, the Department of Justice argues in favor of invalidating protections for those Americans with pre-existing conditions.

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Just prior to the Trump administration's announcement that it would no longer defend key provisions of the Affordable Care Act in an ongoing case brought by Texas and other states, several career Justice Department attorneys withdrew from the case.

"It's pretty simple: new legal position, new team. It's not uncommon to make this kind of switch," a department spokesperson said Thursday night.

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