There are 54 Republicans and 46 Democrats in the Senate, so Democrats need to gain at least four seats to hold a majority.
Figuring out who will control the Senate may come down to which party takes the White House. Democratic vice presidential nominee Joseph Lieberman is also running for reelection to his Connecticut Senate seat. If Democrats pick up four Senate seats and Gore and Lieberman win the White House, Connecticut's GOP governor will likely appoint a Republican to replace Lieberman, giving the Republicans a 51-49 edge.