Thank you for your insight.  Section 302 of the Veterans Benefits and Transitions Act of 2018 states:

"For any taxable year of the marriage, the spouse of a servicemember may elect to use the same residence for purposes of taxation as the servicemember regardless of the date on which the marriage of the spouse and the servicemember occurred.’

My argument is this allows my client to claim her income with her husband in Wisconsin, which means she would file a NR return for MD for 2019, getting all of her MD withholdings back.