MADISON, Wis. -

The Wisconsin Legislature has passed a bill that would exempt from taxes military income for a soldier killed in combat.

The exemption would cover income earned during the year the soldier is killed and in the year before if the soldier hasn't filed a return for that year.

Both the Assembly and Senate unanimously passed the bill Tuesday. Gov. Scott Walker has pledged to sign it into law.

Andrew Johnson's son David, a former U.S. Army first lieutenant, was killed last year while patrolling in Kandahar province in Afghanistan. Johnson says he was shocked to learn that while the federal government would forgive his son's income taxes, the state wouldn't.

Nearly 6,700 U.S. soldiers have died in combat since 2001. About 150 were from Wisconsin.