Warning! Contains SPOILERS for The Falcon and the Winter Soldier episode 4, 

The new Captain America has gone rogue in The Falcon & the Winter Soldier episode 4, but was John Walker evil in Marvel Comics? When Abraham Erskine created the super-soldier serum, he cautioned that it didn't only amplify a person's strength. The serum has a transformative effect upon your character as well, exaggerating all your best and worst character traits. Good becomes great, as seen with Steve Rogers; bad becomes evil, as in the case of the Red Skull.

John Walker would never have been Abraham Erskine's pick to become a super-soldier. He had served his country well on the front lines in Afghanistan, earning three Medals of Honor, but he was a flawed man. Shaken by the realization he couldn't hold his own against the Dora Milaje, and failing to understand those aren't exactly your run-of-the-mill opponents, he decided he needed an edge. And so John Walker took the last dose of super-soldier serum, gaining superhuman abilities that are comparable to Steve Rogers. Unfortunately it didn't take long for him to snap, in spectacular fashion.

Related: John Walker’s Superhero Origin Ignores A Key Phase 1 Line

The idea of an evil Captain America is lifted straight from the comics. Although there are shades of Secret Empire's HydraCap in John Walker's execution of a Flag-Smasher, the main plot is lifted from the far older story in which John Walker became Captain America, but proved himself unworthy to wield the shield.

John Walker's Evil Comics Backstory

John Walker Captain America

Captain America comics have always been political, right from the day he was shown punching Adolf Hitler on the jaw. In the 1980s, writer Mark Gruenwald decided to use the character of Captain America to ask some deep and searching questions about American self-identity. He did so by confronting Steve Rogers with a man named John Walker, who called himself the Super-Patriot and who claimed Rogers' ideals were outdated and worthless in the modern age. The Super-Patriot had been granted super-powers by a criminal organization called Power Broker, Inc., and he worked with other super-soldiers to stage terrorist attacks that he foiled in order to bolster his credentials. Meanwhile, the U.S. government's Commission on Superhuman Activities began to impose restrictions upon Steve Rogers, attempting to strong-arm him into working more closely for them and not for the Avengers. Rogers rejected this, giving up the shield. "To serve the country your way, I would have to give up my personal freedom and place myself in a position where I might have to compromise my ideals to obey your orders," he explained.

The U.S. government turned its attention to John Walker, who had just stopped a genuine terrorist attack in Washington, DC. Walker agreed to become the new Captain America, recruiting one of his pseudo-terrorist associates Lemar Hoskins as his Bucky (later Battlestar). To his credit, he did initially ameliorate his conduct, attempting to prove worthy of the shield.

Why John Walker Turns Evil In The Comics

Captain America 347 Cover

Unfortunately two of the Power Broker's other super-soldiers, Left-Winger and Right-Winger, revealed John Walker's secret identity to the world. Captain America has a lot of enemies, and Walker's parents were killed when they were targeted by a terrorist group called the Watchdogs. Furious, John Walker hunted his old allies down, going so far as to threaten their parents. Captain America #347 saw Walker snap, delighting in the pain he dealt to his enemies before leaving them tied up next to leaking oil-tank and a lit match. Right-Winger and Left-Winger were left badly burned and comatose after the resulting explosion. The commission running superhuman affairs intended to fire John Walker for his indiscretions, but an ill-timed intervention from the president of the United States himself kept him in the costume.

Related: Is Old Captain America Dead? What Did Happen To Steve Rogers After Endgame?

What Happens To John Walker In The Comics?

US Agent with his version of the shield.

In the end, John Walker was forced to step down as Captain America when Steve Rogers uncovered the Red Skull's influence on the Commission on Superhuman Activities, who had been responsible for appointing Walker in the first place. The Commission staged Walker's assassination, and reinstated him as a new hero called the US Agent, arming him with a Vibranium shield. They also messed with Walker's head, removing painful memories and implanting new ones in an attempt to control him. Walker was devastated when he learned the truth, but he chose to carry on serving as the US Agent.

The US Agent has remained active as a government-sponsored superhero ever since, even joining various Avengers splinter groups. He's always been a controversial figure, though, objecting vociferously when Sam Wilson became Captain America and attempted to redefine what it meant to be Cap in the 21st Century; Walker and Wilson swiftly came to blows, and remained implacably opposed to one another.

Is The MCU John Walker Really "Evil"?

Captain America backlash John walker Steve Rogers Falcon and the winter soldier

It's too soon to say whether the MCU's John Walker really is an "evil" Captain America. Clearly he's suffering from PTSD after his experiences in Afghanistan, and the death of Battlestar caused him to snap. The truth is that such a wounded man was never well-equipped to wield the shield and become the next Captain America; Abraham Erskine was far wiser with his choices than the U.S. government.

Unfortunately, John Walker has crossed a line - and the whole world has seen him do so. He used the shield of Captain America to brutally murder one of the Flag-Smashers in what can only be described as an act of vengeance, and it was captured on countless smart-phones. Sadly, while Sam Wilson may have been willing to understand Karli Morgenthau, he's unlikely to be quite so lenient with a man who has brought disgrace and dishonor to the shield of Captain America, so it's likely the murder will prove a Rubicon that John Walker has crossed - and that he will have nobody beside him helping him to stop going further.

Related: Steve Rogers Was Never Perfect As Captain America (And That's The Point)

The super-soldier serum amplifies what is within. For John Walker, that means his repressed anger and pain is exploding to the surface, and his grief and sorrow are all the more powerful. Even Steve Rogers struggled to stay stable after the apparent death of Bucky in Captain America: The First Avenger, but John is unlikely to do so. He may not be an "evil" Captain America yet, rather more an out-of-control one, but he's well on the way to becoming the antithesis of everything Captain America should stand for.

More: MCU's New Captain America Backlash Misunderstands The Point

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