Missouri Sen. Claire McCaskill said she is “bitterly disappointed” that Democrats opted not to hold their 2012 presidential nominating convention in St. Louis, and she suggested that the choice could represent a desire by President Barack Obama’s campaign team to woo the South.

McCaskill, an early supporter of Obama’s 2008 presidential run, said she was “very proud” of the effort St. Louis and Missouri officials made to convince the Democratic National Committee to hold the convention in St. Louis. DNC officials announced Tuesday that they had chosen the other finalist — Charlotte, N.C. — as the site of the 2012 convention.

“I got worried a few weeks ago when all of a sudden they quit returning my phone calls,” McCaskill said, referring to the DNC. “I think I drove them crazy.”

Holding the convention in St. Louis would have given the Show Me State an economic and political boost in a year when McCaskill faces re-election for the first time. She is considered one of the more vulnerable freshman Democrats and Roll Call Politics rates her race a Tossup.

Obama narrowly lost Missouri in 2008, and the state has been a crucial swing state in previous years. But the 2010 elections showed Republican strength and the convention choice could be an indication the Obama team believes North Carolina’s electoral votes are more in play for 2012 than Missouri’s. Obama won North Carolina in 2008, becoming the first Democrat to capture that state since 1976.

Asked if she thought the choice indicated the White House was pursuing a “southern strategy” to win Obama a second term, McCaskill replied, “I think the president and the president’s campaign team have always tried to do things a little differently.”

“There has never been a Democratic candidate for president who put a team on the ground in Utah and Idaho and he did that,” she said. “So I think to try to go counter-intuitive and go into the south for the nominating convention, I understand why that was attractive to the president’s political team.”

But McCaskill stressed that a strong showing in the Midwest would be a key factor in Obama’s re-election.

“He’s got to have the Midwest, and I don’t think anybody should interpret this as giving up on the Midwest,” she said. “I don’t think that’s the case … They’ve decided that the symbolism of going into the South is important … I think you’ll see the campaign all over the Midwest.”