Do you think the Columbine massacre could have been prevented if Klebold's crush returned his feelings?

I don't think any of the girls he had a crush on had any feelings for him. Why would they? The boys didn't talk to anyone else in the school and everyone else thought they were rather unfriendly, if not downright jerks.

And this is all moot speculation anyways. Maybe if the boys' parents' had been more attentative, maybe they would have realized their sons were troubled and needed counseling. That's the only way Columbine would have been avoided.

Well, my opinion on this is it might be possible that he might have done a second thought on the process and idea of whether or not he should go through with it but I have a feeling once he starts showing lack of interest in performing a massacre, Eric would have noticed and might frighten him to get his act together. Since Klebold was quite lonely, he would probably still go along with it out of fear and hopes that it would be like NBK with his girlfriend where she joins in on the thing. I always have a feeling the girl knows about his feelings towards her, I assume the police would have told her and told her why they have to black out her name from the public. Also, Klebold left some hints in his journals about some of the girls he had an attraction for as well. For an example (not the exact quote from his journal but close enough) He had written her name out and mention that her name was weird just like his and questioned if she liked tech-no. The fact that he said her name was weird could be a minor clue on who one of the girls were. Not saying that there was only one girl with a weird name in that school, just his personal opinion. She also probably didn't like him, especially after he killed some people. Taking a chance that someone she cared about could have died because of him. Also he was shy and reserved so she probably didn't notice him and if she did she probably thought that he didn't like anybody and probably avoided him. Even a very thin possibility is that one of the girls he claimed to "love" ended up being one of his victims (try to keep an open mind on that last part).Hopefully my opinions were ideal and understandable and don't worry, I enjoy researching mass murders and murderers including this one too!

No, wanting someone to 'love' is an excuse many psychopaths use to avoid having to take responsibility for being frustrated, no amount of 'love' can take away that desire to terrorize though, so it's a moot point.

It could've been prevented if Therapy, and Counseling were better organized, and more accessible though. Kids like him can be turned around if you get to them before they cross the line.