If all the other toilets flush fine, I think 2 things could be wrong.
1) If the other toilets flush fine, then it's possible the 'problem' is somewhere between the the 'bad toilet' and where it 'hooks up' in the line with where the good toilets work. In other words, as Steve: said, something is in the line or the line is broken.
2) You don't have enough 'draw' in the line that the bad toilet is connected to. Check your Sewer Vents (and I bet you have more than 1) to be sure they're ALL clear. There may be a blockage or something that's fallen down a vent and is preventing air from 'assisting' the flush.
IF this toilet is added AFTER the main house was built, I'm not surprised to hear this problem. Usually, when an inexperienced plumber/homeowner installs an additional toilet in a location like a basement, they don't properly account for proper drainage. And in a lot of cases, this is a disaster waiting to happen. IF the toilet is BELOW the lowest drain vent on your lot, then the basement toilet because the 'path of least resistance' whenever there is a backup. You see, the vent's purpose on the front lawn is to be that point of least resistance in case of a backup. If the new toilet 'bucks' that purpose, the crap will end up in the house.
If you know a friend that is a plumber or if you know a friend of a friend that's a plumber, spend $20-40 for a pro to access the toilet situation. Talk about backups and paths of least resistance. Oh, and be sure your Homeowner's Insurance has a Sewer Backup clause written into it.