Republican consultant Scott Reed says the fact McCain will be 72 when Inauguration Day arrives should play a significant role when picking a vice presidential candidate for the presumptive Republican presidential candidate, the Los Angeles Times reported Saturday.

"By the time this election gets around, everyone is going to know he (would) be the oldest president ever sworn in," Reed said. "It's a concern and it has to be addressed."

Another key factor for McCain to consider regarding a running mate, according to experts, is his unpopularity among many conservatives.

American Conservative Union chairman David Keene told the Times if McCain picks a very conservative politician for his campaign ticket he would endear himself to those currently opposing his candidacy.

"A lot of conservatives fear he's going to change (the party) in some way and redraw it with them on the outside looking in," Keene said. "If you select the right person, you go a long way toward solving that problem."