Paula Abdul has it right—opposites attract, especially when it comes to the 2008 vice president picks. Joe Biden (D) and Sarah Palin (R) each have what the presidential candidates lack.

Let’s take Biden: Senior Senator from Delaware and long-time member and current chairman of the Foreign Relations Committee. His foreign policy and national security experience dwarfs Obama's by decades.

And then there’s Palin: She has little to no foreign policy or national security experience, compared to McCain, but she does have many of the traits this veteran lacks: strongly opposes abortion, favors domestic drilling, and not to mention she’s a woman who’s nearly 30 years younger.

According to Robert Dallek, professor of history at Boston University and pre-eminent scholar on U.S. presidents, while vice presidents never used to be important, "all changed in 1960 when Kennedy chose Lyndon Johnson as his running mate." 

“John Kennedy needed Texas, and he needed the South, and LBJ gave it to him," said Allan Saxe, a political-science professor at the University of Texas-Arlington. "This is similar. McCain needs to get a boost from conservative Republicans and more of the women's vote."

But in the end, will the “opposites attract” philosophy make a difference? Only time will tell…