that's the bottom line the other side can't answer. >> pelley: steve berman and becky anderson. thanks so much. >> woodruff: and we turn to politics, but not the presidential campaign. instead, we focus on what we're calling the "senate six." ray suarez has that. >> suarez: if republicans capture four senate seats, they'll gain control of the chamber. so, the newshour has chosen six key races to follow in the coming months, ones we think will serve as a guide to the battle for the majority this fall. and political editor christina bellantoni is here to explain which contests we've selected and why. why, christina, we should remind people that in every two-year cycle a third of the senate comes up. so out of these 33 seats coming up in the fall, how many are held by democrat and how many by republicans? >> republicans are only defending ten seats and the democrats are defending 23 seats. s which is what happens in the cycle six years after you've won a giant wave election year. in 2006 the democrats took over the senate in part because of races in some of the more traditional red

that's the bottom line the other side can't answer. >> pelley: steve berman and becky anderson.nks so much. >> woodruff: and we turn to politics, but not the presidential campaign. instead, we focus on what we're calling the "senate six." ray suarez has that. >> suarez: if republicans capture four senatseats, they'll gain control of the chamber. so, the newshour hachosen six key races to follow in the coming months, ones we think will serve as a guide to the battle for the majority this fall. and political editor christina bellantoni is here to explain which contests we've selected and why. why, christina, we should remind people that in every two-year cycle a third of the senate comes up. so out of these 33 seats coming up in the fall, how many are held by democrat and how many by republicans? >> republicans are only defending ten seats and the democrats are defending 23 seats. s which is what happens in the cycle six years after you've won a giant wave election year. in 2006 the democrats took over the senate in part because of races in some of the more traditional red states-