The realignment of Barack Obama's presidential campaign in the Upper Midwest will continue this weekend as the Democratic candidate opens his South Dakota office.

The headquarters, on Main Avenue in downtown Sioux Falls, will open Saturday with a kickoff celebration at 2 p.m.

The move comes after a Rasmussen Poll in mid-September showed that GOP nominee John McCain held a 54-37 percent lead over Obama in the typically Republican state. In July, the same poll had Obama within 4 points of McCain.

Earlier this week, the Obama campaign shifted dozens of campaign staff members from traditionally Republican North Dakota to Minnesota and Wisconsin, where recent polls showed McCain gaining.

PAUL WALSH