Doesn't make sense? The President himself states how he and Leon are good friends which typically requires people to know each other a while in order to get to that kind of relationship. RE4 tells us in intro how Leon is assigned to protect the President's family.
It would make sense she would show if he was involved in the story. Sure, it's not set in 2004, but Presidents can be reelected you know and not just in two consecutive terms either. Grover Cleveland was elected President in 1885 and ended his first term in 1889. Then Benjamin Harrison was elected that year finishing his first and only term in 1893. Then Grover Cleveland ran again that year and was reelected with his second term ending in 1897.