An NBC News analysis of housing and voting data show that the counties where it’s most difficult to buy a home saw the biggest shifts toward Trump.

Using its home buyer index to gauge ease or difficulty, the report showed that the top 10% of counties with the toughest markets experienced a median shift of 4.5 percentage points in the vote share toward Trump.

The top 20% with the toughest housing markets saw a 4.2-point shift to the Republican side. That outpaced the nationwide median, which showed a 3.1-point tilt to Trump, according to NBC.

Those differences likely proved decisive in key swing counties as many saw margins separating the parties that were just over 1 percentage point.

The housing market could also help explain why Trump improved his performance in deep-blue states. In New Jersey, for example, Ocean County has the fourth hardest market, and Trump’s share of the vote grew by 7.9 points. Union County is the eighth worst and saw a 14.5-point red shift, while Passaic County came in at 16th worst and surged toward Trump by 19.6 points.

“Housing prices are a big part of the inflation story, especially the most persistent and severe parts of the inflation story,” Bernard Fraga, an Emory University professor specializing in voter turnout, told NBC. “So you can’t separate out the price of housing from voters’ general concerns about the state of the economy.”

To be sure, Kamala Harris offered a housing plan that was praised by some experts as the most aggressive since the post-World War II boom. It included down payment assistance for first-time buyers and encouraged homebuilders to increase housing supply with tax breaks.

Meanwhile, Trump told Bloomberg that he would lower housing costs by easing environmental and permitting rules. But he also has suggested at campaign events that he would limit low-income housing developments in suburbs.

The Republican Party’s 2024 platform blamed high housing costs on illegal immigrants, and vowed to deport them, which some housing experts have said would reduce the availability of construction workers and add to costs. The platform also promised a mix of demand- and supply-side measures.

Early in the 2024 election season, housing had emerged as a major issue. According to a Redfin-commissioned survey released in March, more than half of homeowners and renters said housing affordability was influencing their vote. And almost two-thirds of homeowners and renters said housing affordability made them feel negatively about the economy.

That could also help shed light on another puzzle about the election cycle: even though economic growth and job creation remained solid with inflation slowing sharply, voters were still not satisfied with Democrats’ performance on the economy.

Housing will likely be top of mind as Democrats engage in post-election autopsies and where they need to improve.

Meanwhile, the anticipation of a Trump win and his actual victory sent mortgage rates soaring, worsening housing affordability for prospective homebuyers. While rates eased somewhat after spiking in the immediate aftermath of the election, the 30-year fixed rate is still hovering just below 7%.