[DoodleDawg]

While not considered "property", the Northern states had substantial numbers of un-naturalized immigrants that were not citizens, but still counted fully as residents in the census

No, they were not property. They were free people with rights and interests that needed protection. So they did gain benefit from their representatives in Congress. Slaves did not.

[DiogenesLamp]

No, they were not property. They were free people with rights and interests that needed protection.

But not until two years after a group of states threw off the rule of Washington D.C. *THAT* is when it suddenly became necessary to look after their rights and interests.

Prior to that, they didn't need their rights and interests looked after.