Shimano Index Shifter jams when going to 3rd gear

With this Shimano 3 speed index shifter, I am having trouble with the shifter getting stuck when I try to shift it up to third gear. Even if it doesn't get stuck, I am having a hard time even getting it to shift all the way up into the 3rd index position.

When the cable is not connected to the front derailleur, however, I am able to get the shifter to shift up into the third position.