Democrats have devoted half their advertising spending in midterm races to health care, according to a report released Monday from a left-leaning group that seeks to protect provisions of Barack Obama’s signature 2010 law. 

The survey of recent polling and advertising spending from Protect Our Care underscore a theme that has emerged across the country as Democrats attempt to shift the narrative on 2010 health care law. After eight years of fending off GOP attempts to “repeal and replace” the provisions of Obamacare, Democrats now see their support of the law as one of their biggest strengths. 

“In final three weeks before the midterms, some things may be uncertain, but one thing very clear: Health care is the defining issue of this campaign,” said Leslie Dach, chairman of Protect Our Care. 

Health care was the number one issue mentioned in advertisements for federal races, making up 50 percent of Democratic advertising and 41 percent of total ad mentions in September, the reports said, citing research from The Wesleyan Media Project.

Democrats and pro-Democratic groups ran more than 130,000 ads on health care in September alone, according to the report.

Those numbers are a stark contrast to previous campaign cycles, the report said. It cited a Wall Street Journal analysis that found 29 percent of Republican ads targeted the so-called Affordable Care Act in 2010, while fewer than 6 percent of Democratic ads did. Just 21 percent of Republican advertisements have mentioned health care in 2018, it said.

It also pointed out that “health care” is a top Google search term in more than three-fourths of congressional districts and highlighted Democratic polling that found health care was a priority for voters.

“We’re at this really important moment where not only is health care dominating voters’ thinking about the election and what is at stake, also Democrats have established and maintained a very large advantage,” said pollster Geoff Garin, president of Hart Research.