Obama had no opponent after Jack Ryan his GOP opposition was run out due to the illegal release of his divorce records. Same thing happened to his 2004 Senate Democrat opponent in the primary. Dirty Tricks are Axelrod and Chicago traits.
Alan Keyes stepped in in the hopes that at least he would have a contested race. No one else was willing to do it.
You might not like Ambassador Keyes, you may think he is too vocal in his beliefs, at least he is passionate and has conviction. That is something far too many Republicans in DC do not have.
Only Mike Ditka could have won that race, and he declined to run.