[rfreedom4u]

If secession was/is illegal then why does West Virginia exist?

It should still be a part of Virginia as no state shall be formed within the boundaries of an existing state without the consent of the state and the Congress. Last I checked Virginia never consented to the Western counties forming their own state.

[WhiskeyX]

It became possible when the state goverment of Virginia engaged in treasonous insurrection and rebellion by withdrawing itslef by force of arms from the administration of the laws of the United States during the period of the rebellion. The State of West Virginia was erected during a period of time in which there was no Virginia state goverment to assent or dissent the application of the loyal citizens of West Virginia for accession as a loyal state in the Union.

[donmeaker]

Virginia did consent, as the conquered territory in rebellion had a state government established for it, and their application to have that new state government be represented in Congress included recognition of the new boundaries established by Congress.

[Ditto]

It should still be a part of Virginia as no state shall be formed within the boundaries of an existing state without the consent of the state and the Congress. Last I checked Virginia never consented to the Western counties forming their own state.

In fact, the legal and recognized state government did consent to the creation of West Virginia. Read about The Restored Government of Virginia. It was all done according to the Constitution.