Every seat will matter if Democrats are to maintain their narrow House majority amid a history of presidents losing congressional seats in midterm elections and a Republican edge from redistricting.

The SALT cap has ramifications beyond the individual taxpayers directly impacted, undermining local home values and threatening funding for schools, which are usually supported through local property and state income taxes, Maloney said.

Former President Donald Trump and Republican allies in Congress put the cap in their 2017 tax package to offset other cuts. Critics accused the GOP of targeting residents of Democratic-leaning states with higher taxes and the measure has been deeply unpopular in regions hit hardest, including New Jersey, New York and California.

Democratic Representative Mikie Sherrill picked up a New Jersey district Republicans held for 34 years in 2018 with a campaign that made grievances over the SALT cap a centerpiece. This year she traveled the district in a “Summer of SALT” campaign to promote her efforts to lift the limit.

Some 24% of filers in Sherill’s district took the SALT deduction in 2019 and on average the cap cut it down by $21,996.

“Any time we are fighting for affordability for our citizens, that’s really powerful,” Sherrill, now one of the vulnerable Frontline Democrats, said. “That’s what I was sent to Congress to do so I’m always proud to fulfill all the promises I made -- and this is a big one.”

Representative Haley Stevens also ousted a Republican in 2018 from her suburban Detroit district, where 12% of residents took the deduction.

“It’s really important,” Stevens, also on the DCCC’s priority list to defend, said. “I hear from constituents about it all the time, and it really has affected people’s bottom line.”

Representative Katie Porter, who in 2018 became the first Democrat to represent her Orange County, California, district since it was created in 1983, said the cap was “a very, very big issue” in that campaign.

More than a quarter of taxpayers in her district took the deduction in 2019, on average having it curtailed $18,636 because of the cap.