BOSTON (AP) — Massachusetts Sen. Scott Brown is casting himself as an independent Republican voice and Democratic rival Elizabeth Warren says she’ll guarantee women equal pay as the nation’s costliest Senate contest races toward an Election Day finale. But for all of the cash and careful messaging, the result could hinge on which campaign is better organized to turn out voters.

“I’ve kept my promise to be an independent voice. I put people ahead of politics and now I need your help to keep that independent tradition alive in Massachusetts,” Brown says in his final ad, which features him embracing voters and driving his pickup truck. But it avoids any mention of Brown’s party affiliation. While Massachusetts is home to fellow Republican Mitt Romney_whose campaign Brown has endorsed_the only image of a presidential candidate in the 60-second ad is Democrat Barack Obama. The president holds a commanding lead over Romney in the state.