council is mainly a popularity thing when election is left up to student voting. In many schools there is a minimum GPA to run for office but from there, the only way someone who isn't popular is going to get in is if there isn't anyone else popular running for the same office, it's a position that teachers vote on instead of students, or if no one is running against them. Sad but, true. Occasionally a kid who has office access will rig the voting to sway things away from the popular kid and perhaps sometimes there aren't any running mates for some of the lesser "cool" ASB positions.
At my school a majority of the ASB offices were elected by vote of fellow students. One position however (the only one where anything important was actually performed or that required quality control) was chosen by staff rather than students. That just so happened to be the position I held for 2 years in high school. I was required to help keep the books, handle check reqs and payment for classes, clubs, and sports, and given access to the safe so they wanted to know an idiot with sticky hands didn't get elected.
On the bright side, there are popular kids that are also smart and do very well in school and make good decisions in their personal lives as well. There were a couple other kids in ASB in the years I participated that had a clue, worked hard, and weren't stuck up, screwups and were popular all the while.
ETA: out of the 7 or so position in the ASB only 2 actually had duties that weren't just busy work to make it seem like there was enough for them to do to fill up a 50 minute class time slot. Myself and another person spent our ASB hour in the business office with the bookkeeper working. The rest of the ASB spent there time wandering the halls pertending they were on official business or sitting in their class (half the time unsupervised because the instructer was a total dip). In the ASB class their only real duties as ASB members were to come up with themes for spirit week, make posters to hang in the halls, and make decorations for pep-cons (assemblies to pump kids up for football and basketball games... the only two sports the school felt like paying attention to). Most kids run for office because they get to stand out front and participate in assemblies, do intercom announcements, and most importantly get out of class for nonsense that doesn't matter.
to an extent, like others mentioned, many of the popular, jock-type kids were in honors classes and got good grades... but usually made up for that by spending their weekends hung over (high school... not middle school). And don't think favortism doesn't exist between students and teachers. At my school I honestly noticed that there were still a lot of TEACHERS trying to fit in with the cool kids and being much easier on them. And for the record, honors isn't all that advanced. Taking trig at the local college while you're in hs would be worth a mention... honors... eh, not so different from regular classes. Often times I found there was much less fluff in the regular classes which left more time for real study. I took some honors and it's really not a lot to brag about.