War Exclusion Clause
  
It's an insurance industry fine print codicle to the codicle which says that the insurance company will, in fact, fund the reconstruction of your home if it burns down...unless that burning was caused by war. See General Sherman and his fine march for details.
But for most insurance companies, wars are classified in the same vein as "an Act of God," in which case all financial bets are off. Financial liabilities to the insurance company are excluded in the event of war.