My American wife refuses to return to Israel with our children after a Summer vacation in the U.S.A ,since Operation Protective Edge, even though there is a cease fire and schools have re-opened. She claims it is unsafe (we live in the South where many rockets were fired) but I think it's an excuse to cover up our failing marriage and her desire to move there. What legal action can I take to get my kids back?

Bring Hague Convention proceedings at your local Israeli family court  for the return of your children under the 1980 Hague Convention on the Civil Aspects of Child Abduction, which binds both Israel and the U.S.A. If you only consented to your children travelling to the States for a holiday then their continued presence there would appear to a passive form of child abduction (wrongful retention) and you can apply for an order for the children's return to Israel, their country of habitual residence.