The US would have most likely still gone to war with Spain even without the explosion of the USS Maine.
This is due to the fact that US newspapers were constantly writing about and showing pictures of Cuban citizens who were starving, unsafe, and unhealthy under the control of Spain. America's need to help Cuba falls under the idea of the Monroe Doctrine, in which the US is supposed to be the protectorate of the Western hemisphere. This is why the US felt obligated to help Cuba become independent from Spanish colonial control.
This sentiment would have probably drawn the US into war even without the attacking of the USS Maine.