The 737-200 can typically fly about 1900nm, however with the right engines, loads, and reserves you could take one over 2000 nm easily.
Edit: The distance from PHX-STL is 1262nm according to the great circle mapper, so effectively a 732 could fly from PHX-STL, turn around and fly 2/3 of the way back to Pheonix if it had to.
[Edited 2004-02-15 19:10:52]
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