Sen. Barack Obama expects to reach a primary season milestone when the Kentucky and Oregon polls close Tuesday night, but he won't be in those states.

He will have won the majority of pledged delegates earned through election contests — and he'll head to the state that delivered his first victory in January.

The campaign announced today he will hold a rally Tuesday night in downtown Des Moines.

Obama aides have long said they consider Iowa a true fall battleground, and in a release call the Hawkeye State "a critical general election state that Democrats must win in November."

— Christina Bellantoni, national political reporter, The Washington Times