But how heavily do voters weigh the candidate's choice for a running mate?
Some people who talked to Action News said, it matters a great deal.
"Previously the Vice Presidency was not that active, but nowadays it's changing, and it seems like it's going to be a tag team presidency" says Arman Chodruay of University City.
Some people, however, are not convinced it's that important.
"I think he just piggybacks onto what the President does, and implements his policies," said Miguel Gonzalez of University City. "So, it's really not going to make my decision for me."
For some voters, the V.P. pick becomes more important when the focus turns to presumptive republican nominee John McCain.
"Because of his age, yes a young man can also die suddenly," said George Lakey of West Philadelphia, "But, for me, the vice presidential pick matters more for him."
Some experts add, it's more important for a presidential candidate to pick a running mate that won't hurt them, rather than one that will help them.
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