Of the two major parties in this country, it is only the Republicans who, for purely ideological reasons would split the vote to "send a message" like they did in 1992...the stupidity of that action gave us one Clinton in the White House and if repeated, will give us another.
The libs did it in 2000 with Ralph Nader. It's a matter of how much the base of a party is willing to hold its nose to win the White House. Odds are, the GOP base will be less willing in 2008 - and the Bush Admin is giving them good reason to be annoyed over illegal immigration.