Romney's not a winner in the jobs department either, let's face it.
To me politicians' ability to create private sector jobs is like waters' ability to create fire. Water kills fire instantly but the only way fire is created is to keep the area dry and eventually conditions will be right for the formation of fire. Same hold true for government. Keep politicians away and private sector jobs will eventually be created when the conditions are right. Invite political meddling and you'll kill the private economy.
And let's not forget that Romney had legislature dominated by democrats during his term as governor.
Politicians don't create jobs, but their policies can make it harder or easier for the private economy to do so.