Public Policy Polling says Mitt Romney and Barack Obama are tied in Missouri -- 45% each, with 9% undecided.

Obama beats Newt Gingrich 49%-42%, Ron Paul 45%-43%, and Rick Santorum 47%-44%.

The poll is attached below.

A close Missouri race might put the state back in play, with millions in TV advertising and campaign appearances this fall.

Most observers -- Republicans and Democrats -- have said for months they think Missouri is no longer in play, but a slightly red-leaning state.