Senate battles intensify with money, ads and big-name surrogates WASHINGTON -- The race for the Senate has intensified, with big-name surrogates and new money and ads moving into criucial battleground states in this final week of the election. Senate Majority Leader Harry Reid will cast his early vote Wednesday at Cardenas Market in Las Vegas, a nod to the power of the swing state's Latino electorate in the competitive race the between Democratic Rep. Shelley Berkley and Republican Sen. Dean Heller. In North Dakota, Sen. John McCain was set to stump Thursday for fellow Republican Rick Berg, the congressman who is in a surprisingly close contest with Democrat Heidi Heitkamp, a seat the GOP had counted in their column in their pursuit of the Senate majority. Heitkamp got an assist earlier this week with a visit from former President Clinton. Republicans need four seats to flip control of the Senate from Democrats - three if Mitt Romney becomes president and his vice president is the tie-breaker - but Democrats have held the advantage after candidate missteps in several states. Outside spending from the powerful American Crossroads and Crossroads GPS groups aligned with Republicans have unleashed an onslaught of new ads in 10 states, pumping more than $10 million into the battle for Senate control. A counter-assault was announced Wednesday by a Reid-aligned Democratic group, Majority PAC, which launched new ads in seven key states. While economic issues dominate the Senate races, social issues have complicated the battlefield for Republicans after candidates in two key states - Indiana and Missouri - made rape-related comments reflective of their hard-line anti-abortion positions, which led many Republican supporters to back away. The Indiana race between Republican Richard Mourdock and Democrat Joe Donnelly has become a toss-up, according to analysts, after Mourdock's suggestion that a pregnancy from rape was "something that God intended." His campaign is being helped by the fiscally conservative Club for Growth, which added additional money to its ads attacking Donnelly on economic issues. And in Missouri, Todd Akin has been able to remain competitive against Democratic incumbent Sen. Claire McCaskill despite the Washington GOP's near-abandonment of his campaign after his comments that pregnancy rarely results from "legitimate rape." Republican Newt Gingrich has been stumping for Akin this week as McCaskill took time out because of the death of her mother, and Gingrich sent out a fundraising appeal calling Akin "a man of principle and conviction." At the same time, races that had appeared to be settling have received new attention. Crossroads put up an ad in Nebraska, where Democrat Bob Kerrey, the former senator, has narrowed the fight with Republican Deb Fischer in a race that has long tilted toward the GOP. And Democrats sought to bolster their candidate in Connecticut, Chris Murphy, a decidedly blue state where the Republican, Linda McMahon, the former wrestling executive, has posed a strong challenge.