House Democrats' campaign arm is instructing allied super PACs to promote minor candidates in several key House races, Axios has learned. Why it matters:

This allows Democrats to steer outside groups toward siphoning votes from Republicans without violating laws against direct coordination.

• An Axios review of the Democratic Congressional Campaign Committee's "redboxes" — publicly available webpages laying out what PACs should say in ads and which voters to target — found references to minor candidates in five races.

• The DCCC included language on four of those pages promoting a third-party or independent candidate with language touting their conservative, pro-gun or anti-government bona fides.

"Registered Republicans under the age of 55 need to see ads," the redbox for Colorado's 5th District says, "showing that ... Christopher Mitchell, a libertarian, is the true conservative running for Congress."

• The page for Virginia's 2nd District says white, college-educated men should see that independent J. Matt Baker is "a staunch supporter of the 2nd amendment" who will "defend our constitution."

• In Virginia's 5th District, the DCCC wants the same group of voters to know that independent Cooke Harvey "will fight for Virginia's farmers against big government."

• Republican women in Nevada's 2nd District should be informed that American Independent Party candidate Lynn Chapman "has spent decades fighting for conservative values," the DCCC says.

Zoom in: In several cases, the redboxes urge super PACs to steer Democratic and left-leaning voters from minor candidates who could siphon votes from the DCCC's recruit.

• The redbox for Alaska's at-large district — where Democrats are backing independent Bill Hill — says voters need to know Eric Hafner is a "fake Democrat" despite being listed on the ballot as one, noting he is an inmate in New York with no clear ties to Alaska.

• The page for Virginia's 2nd District urges PACs to ding the progressive credentials of another independent candidate, Geral D. "Bishop" Staten, a self-identified "Democrat Socialist."

• Black voters should hear that Staten "said that he would vote for Donald Trump in 2024 and said that President Obama is a quote 'puppet and a clown,'" the DCCC redbox says — though he has denied supporting Trump.

Between the lines: In the post-Citizens United era, redboxes have emerged as a way for campaigns to give messaging guidance to cash-rich outside groups that often have less localized knowledge of their turf.

• The practice is so named because the websites often put a red box around the instructions.

• The NRCC has its own publicly available redboxes, though it shies away from encouraging PACs to boost spoiler candidates. The big picture:

There have been several other isolated examples this year of both parties allegedly boosting spoiler candidates, including with redboxes.

• Democrats successfully sued last month to get a Green Party candidate who they alleged was a GOP plant booted off the ballot in Pennsylvania's 7th District.

• Republicans in Alaska tried and failed to do the same with unaffiliated candidate Dan J. Sullivan, who they allege is a spoiler for Republican Sen. Dan S. Sullivan in his race against Democrat Mary Peltola.

• It's even happened in party primaries: The campaign of Rep. Doris Matsui (D-Calif.) put language on its redbox promoting Republican Zachariah Wooden in the hopes of keeping progressive challenger Mai Vang out of the general election.