The Dems overplayed their hand bill. You will find that they made that mistake in the 2004 for elections and were resoundingly throttled for it. One can only hope that they come up with more legislation like this in time for 2006.
It is foolish to assume that Arnold will veto this monstrosity.
If he does, he'll gain some social conservatives in next year's election (most of the social liberals already having been driven into the anti-Arnold camp by propaganda).
However, it will not cost the Rats any seats in the legislature -- unless there is redistricting. Then it might cost them two, at most.
What it might do is marginally increase Republican and conservative turnout in this year's special election. If it's handled properly, i.e., used.
Arnold must not only veto the bill, he must do it with a big splash.
In 2004, not a single California district flipped parties. As they are currently gerrymandered, CA legislative seats are good as gold, with only primary challenges to concern them.