Yay! Sharp is probably the only Democrat in Texas, besides Mayor Bill White, who can win the open seat.
Corrected. 
As to Nym's question, since this will be a special election, you can't make the types of assumptions that I think Nym wants me to make. 
In fact, throw most of your assumptions out of the window.
Special elections for open Texas Senate seats are weird. Usually, you get tons of candidates who split the vote a million ways and the top two who survive that mess get to the runoff.
My first concern for Sharp is getting past this jungle primary. Especially if there's a Hispanic or Black in the mix.
Hey, I'd love to hear you say Sharp can win.
Just trying to predict your predictions in advance, that's all.
I have to think Sharp would have trouble matching Obama's performance in the suburban areas, which would kill any chance he'd have of winning. Then of course there's the fact that Obama being in office hurts any Democrat in the rural parts of the state, even Sharp (just him less so than others).
But yeah, obviously special elections are weird. Turnout as always is critical. Obviously Sharp could win if the GOP comes up with a bad candidate (gotta think there's a deep bench in Texas though...just a matter of whether there's a divisive primary and all probably).
