The ICC would require Congress to ratify it anyway, so Obama isn't really the issue.  I believe Clinton supported it, but, as with Kyoto, obviously it didn't have a snowball's chance in Hell under Gingrich.  As it would apply equally to Obama, I don't see the obvious partisan politicking inherent to supporting it.  If anything, it could be sold as imposing accountability on politicians, which is fairly popular at the moment with the public.

As to prosecuting Junior, that's up to Eric Holder, assuming he's confirmed (unfortunately he seems to be the one nominee the Reps are trying to stop).  He's been getting an earful on it from the grassroots activists (even responded with "Enough, folks, I hear you"), but I doubt they're going to prosecute, because it's too easy to take the chickenshit way out.  That said, even if they were planning to, they wouldn't say so, because Bush would simply start issuing blanket pardons.

Be nice to America. Or we'll bring democracy to your country.