WARNING: The following article contains spoilers for Captain America #17, by Ta-Nehisi Coates, Jason Masters, Matt Milla and VC's Cory Petit, in stores now.

Ta-Nehisi Coates' Captain America is one of the most unapologetically political runs the book has ever seen. It recently tackled white supremacists and toxic masculinity in a group known as the Watchdogs who are going after immigrants and refugees in America. Now, Steve Rogers has to deal with another major issue -- cop killings and the civil unrest that inevitably follows.

But as Cap works with Sharon Carter, Misty Knight and the Daughters of Liberty to solve this problem, he discovers matters are even more complicated thanks to the rise of his very own Punisher: the new Scourge.

RELATED: Marvel Just Brought Back Captain America's Deadliest Foe From the 1980s

Cap and Punisher go way back, with Steve Rogers being the only man Frank Castle respects. While Frank's a war vet who's willing to kill criminals because of the death of his family, the one man he'll listen to and stand down for is Cap, as seen in Mark Millar's Civil War. It's why Frank turned to Hydra in Secret Empire, as he views Steve as an idol, but still, Cap -- as much as he feels sympathy for Frank -- knows he's a war-dog that needs to be caged for his own good.

This arc sees Steve hunting Scourge, believing this new gunman is going after innocent NYPD cops. With police brutality being a problem, Cap doesn't want more trigger-happy cops out there seeking to avenge their fallen comrades, and with tensions high, he tracks down clues from the death of a lawyer, Angel Larimore. He discovers through an acquaintance called Tony that Angel was actually working to expose a group of rookie cops Scourge killed.

RELATED: Captain America: Brooklyn's Bronze Statue Gets in the Holiday Spirit

They weren't innocent as initially presumed, however, as they were corrupt and possibly on the payroll of Kingpin/Mayor Wilson Fisk and maybe even infiltrated by the Watchdogs. Steve knows the NYPD has dirty cops on the inside but for someone to weed them out in this fashion, it's a powder keg waiting to explode. But Scourge has no problems and that's why he gunned down this squad of policemen, realizing they killed Angel for holding evidence against them. Scourge is actually an avenger, a vigilante showing no mercy just like the Punisher.

It comes to a head when the Watchdogs attack Tony's home, killing him in front of his wife, Steve and Misty. It's a brutal brawl and just when it seems the heroes are outnumbered, the new Scourge shows up, shooting most of their attackers before disappearing. It's exactly how the Punisher operates, leaving Steve worried because apparently Scourge also assassinated Fisk in his war against crime. That's unlikely to stick, though, as it could be a fake-out by Fisk to go into hiding, but Steve knows Scourge, a decades-old enemy who's toed the line between vigilante and murderer in the past, is now totally unhinged and relentless in his pursuit. Cap knows the vigilante's actions could lead to more attacks on politicians and policy-makers.

RELATED: U.S.A-Hole: The 'Worst Captain America Ever' Just Destroyed Steve Rogers

Scourge is no longer an enemy that wants blood for the fun of it, he's calculated and seeking justice in the worst way possible. They deduce he's Antony Diaz, a war vet from Afghanistan who worked with Angel in the past, and while the Scourge identity was something Thomas Holloway funded with various people donning the masks over the years, now it's a symbol of vengeance and social justice that could undo everything Steve has worked for. The masses have joined a Scourge movement, with the villain becoming a symbol of rebellion just like U.S. Agent warned Steve they would in the last fight, and if they're going to stick up for the new renegade on the block, Steve knows his shield won't be enough to save them from the police.

Captain America #18 is on sale now.

NEXT: The Avengers Have Been [REDACTED] By SHIELD?!