The spending surge was driven in part by Kentuckians Not Corruption, a Democratic PAC formed in mid-August that spent about $2.3 million — roughly $1.5 million against Republican Alvarado and $750,000 in support of Dembo. The group was created to counter Republicans' financial advantage in the district, said Kelsey Coots, a general consultant with Blue Dot Consulting who worked with the PAC.

"Zach was an outsider. He'd never been an elected official, and so he was going to be spending all the time introducing himself," Coots said. "And we had a feeling that, of course, the Republican side, specifically Trump's No Going Back PAC would be in the fight, and so we had a conversation about how we could support the Democratic side in the race."

No Going Back, affiliated with President Donald Trump's political operation, spent more than $5 million in the district — $2.5 million backing Alvarado and $2.5 million opposing Dembo. Overall, PACs spent about $1.4 million supporting Dembo and $3.8 million opposing him, while Alvarado benefited from $3.8 million in support and faced $4.5 million in opposition.

Other pro-Dembo groups included Gov. Andy Beshear's In This Together and the House Majority PAC, which works to elect Democrats to Congress. Coots said polling showed corruption in politics and affordability were voters' top concerns this cycle, and that Republican-aligned PACs "did not have an answer to that."

"(PACs) can be messengers for things that maybe a candidate wouldn't say," she said. "In our instance, we wanted to talk about corruption. We know that that is the issue that's number one on Kentuckians' minds, and there was a lot to talk about in that 6th Congressional District race."

In the final days before the election, PACs also trained fire on third-party candidates. No Going Back spent more than $50,000 on mailers and texts opposing Independent Jay Bowman and the Kentucky Party's Pete Lynch. A newly formed group called Our Heritage Matters spent nearly $220,000 between Oct. 21 and Nov. 3 promoting Bowman; the group has also spent on ads supporting third-party candidates seen as spoilers for Republicans in other states.

Outside the 6th District, PAC spending in Kentucky's other congressional races was far smaller. Save America Freedom spent about $35,000 supporting Republican Ed Gallrein in the 4th District, and a Planned Parenthood Alliance PAC spent $2,600 backing Democratic U.S. Rep. Morgan McGarvey in the 3rd.

At the state level, PACs spent more than $1.8 million on General Assembly races, according to state campaign finance records — about $1.1 million on 46 House candidates and nearly $650,000 on six Senate candidates, with much of it concentrated in suburban Lexington and Louisville districts.

The largest statehouse spender was the Commonwealth Conservative Coalition, which put up about $876,000, or roughly 48% of all legislative PAC spending. The group spent about $800,000 opposing House Democratic candidates, including more than $186,000 against Suhas Kulkarni, who unseated Republican Rep. Ken Fleming in Jefferson County's 48th House District, and more than $250,000 against Tim Hall, who defeated Republican Rep. Susan Tyler Witten in the 31st. It also spent $96,000 against Democratic Rep. Adam Moore, who held his Central Kentucky seat against former Republican Rep. Killian Timoney.

In the week before the election, the coalition spent $35,000 backing Republican House Whip Jason Nemes and about $9,500 supporting Rep. Daniel Fister of Versailles. Fister won reelection; Nemes lost to Democrat Jennifer Hardin. In the Senate, the coalition spent nearly $74,000 opposing Sarah Cole McIntosh, who defeated Republican Sen. Julie Raque Adams in Jefferson County's 36th Senate District.

Other groups active in legislative races included Americans for Prosperity, which spent more than $130,000 supporting Republican House candidates and more than $67,000 for Raque Adams; GOPAC, which put more than $188,000 behind Raque Adams; the Kentucky Chamber Advocacy Committee, which spent nearly $46,000 on Republican Senate candidates and nearly $87,000 on Republican House candidates; and the Republican State Leadership Committee, which spent about $154,000 on the 36th Senate District race.

The National Association of Realtors Fund spent more than $65,000 on Raque Adams and $30,000 supporting Witten. The NRA Political Victory Fund spent $1,120 on Republican House candidates and $1,110 supporting Sen. Lindsey Tichenor, who lost to Democrat Christan Furman in the 6th Senate District.

On the Democratic side, Planned Parenthood Action Kentucky spent about $26,000 supporting Democrats and opposing Republicans in House races, plus nearly $300 for Sen. Karen Berg in Jefferson County's 26th Senate District. Protect Freedom PAC spent about $91,000 supporting Tanner Hesterberg and Marianne Proctor in the House and more than $45,000 supporting Tichenor. Yellowbanks Political Action Committee spent nearly $3,400 supporting House Democrats and $1,100 for Vicki Quisenberry against Republican Sen. Gary Boswell in the 8th Senate District.

The totals underscore how outside groups — barred from coordinating directly with candidates but free to spend unlimited sums independently — have become central players in Kentucky elections, shaping messaging on corruption, affordability and third-party spoilers while voters decide the outcomes.