True, but if the union is unstable enough or distracted with domestic issues a confederate victory is not out of the question. If the CSA stays more organized they could win more by catching the union in a bad position more so then individual merit. People downplay the power of lobbying in the US. Third party interest presents a much larger issue in the US then it does in the more unitary states like seen in European. The north might have to worry about short term business interest unintentionally screwing them.
Except there wasn't any real Third Party interest that was that strong. The few mill owners who were hurt by it were greatly outnumbered by the steel mill owners, the arms industry, the miners etc. who had to feed the Union war machine.