Depending on the economy, Palin could easily beat Obama in 2012. If the economy stinks, Palin beats Obama. If the economy is great, Obama beats Palin. At least that the way it usually goes. When the economy is fantastic, the incumbent usually wins. When the economy is terrible, the incumbent usually loses.
If Palin could easily beat 0bama in 2012, then any one the GOP nominates could be him with even greater ease.