The events of Civil War II left a stain on the legacies of both Hawkeye and Daredevil. It is during this Marvel event that Hawkeye fatally shoots the Hulk and Matt Murdock, sadly, doesn't come to Clint's defense.
Prior to the shooting, Bruce Banner—who had not Hulked out in a year—was in a rather intense situation. After the psychic Ulysses claimed to have had a vision so terrible that he and the Avengers needed to stop Banner as soon as possible, an argument ensued. Things only escalated when it was brought to light that Banner had secretly been experimenting with Gamma radiation again. Banner claimed that these Gamma radiation experiments are what was keeping him from Hulking out for so long. Things only continued to escalate until Hawkeye suddenly shot Hulk from a distance. Hawkeye claimed that he saw green in Bruce Banner's eyes, signaling he was seconds away from Hulking out, but no one else could agree with Hawkeye's recollection. Nonetheless, Hawkeye willingly turned himself in to the proper authorities.
The ensuing trial would take place in Civil War II: The Accused by Marc Guggenheim, Ramón F. Bachs, and Garry Brown. Matt Murdock serves as the prosecutor, and he seeks to get Clint Barton the death penalty. For Matt, this isn't personal. He neither loves nor hates Hawkeye, he just feels like it is his duty to pursue the death penalty under the law in honor of a fair trial. Granted, Daredevil does decide to help Hawkeye when he finds out he's not getting the fair trial that he should, but not in any way that's intended to get him off the death penalty.
Daredevil's Betrayal: Does Hawkeye Really Deserve The Death Penalty?
High-stakes conflicts like this between superheroes often happen due to a misunderstanding or is a result of mind control, but this is a rare instance where neither being the case. Matt Murdock perfectly understands what transpired on the day Bruce Banner was murdered and still tries to get Hawkeye put to death by the state. It's shocking to think that despite his personal relationship with his fellow Avenger, Matt doesn't understand that Hawkeye wouldn't kill Hulk unless he genuinely believed everyone was in danger. Truthfully, because of that relationship (which includes them both being romantically linked to Black Widow), Matt probably should've forgone taking part in a trial like this, but that is a whole other conversation altogether.
The fact remains that Daredevil tried to get another superhero put to death. There is very little that can justify Daredevil's actions, let alone redeem him. Even if he didn't achieve his goal, the fact that Daredevil even tried to get Hawkeye put to death leaves a bad stain on both superhero and law careers.