In 2006, these sidekick cautionary tales were brought back to life, flying in the face of readers' acceptance of their continual rest. But whose return was best?
Before we get to their return, let's rundown how they started.
James Buchanan Barnes was an orphaned young man who lied about his age to get into the Army so that he could serve his country and was stationed with Steve Rogers. He stumbled upon Rogers donning his Captain America uniform and was appointed Captain America's sidekick. An accomplished brawler before training, Barnes took to the military training with gusto, making him an excellent counterpart to Cap and a stealth agent able to pull operations Cap couldn't.
Cap and Bucky fought in World War II during most of America's involvement. Sometimes they pulled off missions with Sgt. Fury and his Howling Commandos and others they operated with the superhuman group, The Invaders. When Cap and the rest of the Invaders were captured by the Red Skull, Bucky assembled the Liberty Legion to rescue them and led that group for awhile, as well as the Kid Commandos, a junior version of the Invaders. Their last mission was infiltrating a stronghold of Baron Zemo, but the duo were tied to a rocket and launched. They freed themselves and redirected the missile, but, as Cap jumped away, Bucky couldn't get away in time and the missile exploded.
Jason Todd was an orphaned young man who lived on the streets of Gotham City. He was found by Batman in the process of stealing the tires off the Batmobile. Seeing something in the kid's chutzpah, the Dark Knight decided to train Todd like he had trained Dick Grayson before. Jason took to the training and became the second Robin.
It wasn't long before Jason became rebellious. He would disobey orders, go looking for fights(but not in a crimefighting way) and even may have killed a diplomat's son who attacked a woman. Getting a lead on his birth mother, Jason chose to go it alone and walked right into a set up by the Joker. After beating him mercilessly with a tire iron, the Joker left Jason and his mother in a warehouse with a bomb. Like Bucky, he couldn't get away.
As it turns out, Bucky did not die. Like Cap, he was preserved in the frozen waters, sans his left arm and barely functional, yet still retaining his fighting reflexes. Like Jason Bourne. Found by a Russian sub commander who had an earlier encounter with Cap and Bucky, Bucky was fitted with a cybernetic arm and was conditioned to operate for his new Russian handlers. He was their secret weapon, an assassin who could kill without being caught and received all the training Captain America had.
When not on assignment, Bucky was kept in suspended animation, deemed to likely to bail if given too much freedom. To the intelligence community, he was called "The Winter Soldier" and with the fall of the Soviet Union, he was picked up by Aleksander Lukin, an industrialist with dreams of returning the Soviet Union to glory.
The Red Skull, who transferred his consciousness into Lukin after being shot by the Winter Soldier, tried to have Bucky kill Captain America during a plot to power the Cosmic Cube, but Cap used the Cube to reawaken Bucky's memories instead. Disoriented and dismayed about being used, Bucky dropped out of sight for awhile, but came back into action as an agent of Nick Fury.
At the end of Crisis on Infinite Earths, four people went to specially created universe to live in peace while New Earth found it's way. They were Superman and Lois Lane of Earth-2, Alexander Luthor of Earth-S and Superboy of Earth-Prime. Long story short, Luthor and Superboy went round the bend in their loneliness and decided to remake the universe to their liking. Superboy-Prime, as he was called while Kon-El was around, had tremendous power and his repeated attempts to break free of the crystalline walls of their secluded dimension had reality changing effects on the universe.
One change was that Jason Todd didn't die from the injuries sustained from the Joker(Apparently, even though it happened without any cosmic disturbance, his death wasn't supposed to happen and Superboy's punches set it right. Not even in comic logic does that make sense). Only thing was, he returned where his body had been: in his grave. The mad drive to escape his coffin coupled with the untreated injuries left Jason Todd addled and touched in the head. But, like Jason Bourne, he still had all his skills ingrained into his reflexes, so it was easy for some homeless guy to recognize him as Robin and sell that info indirectly to Talia Al Ghul.
Talia placed Jason into a Lazarus Pit and when he emerged, he found the newsclippings Talia had left showing that after Joker had killed Jason, Batman just put him back in Arkham. Jason thought that Batman should have killed Joker, to avenge Jason's death. Jason went back to Gotham and, using an old identity of Joker's, started his own vigilante career. As the Red Hood, Jason severed drug dealers' heads who sold to kids and took down Captain Nazi permanently(not really, but you get the point). He confronted Batman many times, culminating with a three way stand-off between Batman, Red Hood and the Joker.
An inconsequential C-4 explosion and Infinte Crisis later, Jason Todd spent some time as Nightwing before redonning the Red Hood guise. He now is working alongside Donna Troy, the new Atom and New-Earth's Monitor to find Ray Palmer.
Unless you were around in the 40's to read the original Captain America and Invaders comics or in the 70's for that volume of The Invaders, your impression of Bucky is pretty much that guy who blew up when Cap got frozen. Still, that's better than being the Robin Voted to Die.
As far as methods of resurrection, Superboy-punches are, by far, the lamest reasoning imaginable. It's not the whole restructuring of reality that perplexes you, it's the image of Superboy hitting the "walls" of reality. In Bucky's case, the Cosmic Cube was right there but was not used as the catalyst for his return. He was always alive, just changed into a badass assassin. And really, being killed in a flashback story with the only eyewitness being a guy falling from the sky and probably suffering from a concussion from an explosion is just begging someone to bring him back.
As it is, Jason Todd is the pouty black sheep of the Bat-family and Bucky is the Winter Soldier, a man who gives Iron Man pause.
THE WINTER SOLDIER!!