Stormcloaks Or Empire (One Of The Three Certainties Of Life)

[Keltest]

This is true, but it's also irrelevant. The Legions might think that a war with the Dominion is coming but the more likely option for an Imperial victory in the civil war is the Dominion working its way further and further into the Empire's power structures until the Empire can't resist anymore.

This is shown in Solitude, in that the Thalmor own or have the support of half the Jarl's court including Elisif, the Imperials own candidate for high queen.

Even the Imperials know that Elisif is not a strong or independent queen. She may or may not end up deferring entirely to Tullius during her reign as queen, but the Dominion being able to get in the good graces of her court means very little.