Rep. Joe Donnelly (D) led state Treasurer Richard Mourdock (R) by 2 points  — a stastical dead heat — in a new bipartisan poll of the Indiana Senate race released today.

Donnelly led Mourdock 40 percent to 38 percent in the Howey/DePauw University Indiana Battleground Poll. Libertarian candidate Andrew Horning received 7 percent in the survey.

The results mirror several Democratic internal polls released over the past several months. Sensing an opportunity, Democratic groups spent heavily to boost Donnelly’s campaign over the summer.

But Republican groups responded in kind, with American Crossroads hitting the airwaves with seven-figure ad buys blasting Donnelly in September.

The poll of 800 likely voters was conducted Sept. 19-20 and on Sept. 23.  The margin of error is. 3.5 percent. According to Howey Politics Indiana, the poll surveyed 43 percent Republicans, 38 percent Democrats and 19 percent independents.

The poll also showed GOP presidential candidate Mitt Romney ahead of President Barack Obama, 52 percent to 40 percent.