Now this does raise the question of who exactly these 12% not-liberal-enoughers are. I, for example, might wish Obamacare was more liberal than it is, but I still won't say I oppose it. There are some Americans who really are left-wing enough so they oppose, on substance, mainstream liberal policy objectives, but I don't think they total 12%. There's probably some remnants of the firebagger wing of the party mixed in here. And there are probably some people who, unlike me, will vote "opposed" in a poll question of this sort of they can conceive of any policy they'd prefer to Obamacare, even if they don't find the law itself to be particularly objectionable.
In all cases, to say such people won't vote Republican is not to say they will vote Democratic, but obviously to the extent that 12% has a lean, it will lean in favor of the Democratic Party.