BZZZZZZZZZZZT...Wrong.
The Federal Government taxes all of my husband's income......the Commonwealth of Virginia (home state) taxes a part of it as do the states of Delaware and Maryland.
Your income is fully included in your home state return. Just like those smokers who happen to pay and out of state tax on cig's, you get a credit for the amount of tax paid to another state. If this tax paid to another state equals or exceeds your home state tax their is no add'l amount due.
However, ALL your income is subject to your home state tax.
If you folks got your wish then the only remedy that states would have is either federalize the tax thru the federal gov't or do it by agreement.
You folks really don't want the remedy you suggest. Trust me.
PS. You too, really ought not do your own taxes.