Poland signed the largest arms procurement deal in its history on Wednesday, agreeing with the United States to buy Raytheon Co’s (RTN.N) Patriot missile defense system for $4.75 billion in a major step to modernize its forces against a bolder Russia. “It is an extraordinary, historic moment; it is Poland’s introduction into a whole new world of state-of-the-art technology, modern weaponry, and defensive means,” President Andrzej Duda said during the signing ceremony. NATO member Poland has accelerated efforts to overhaul its ageing weaponry following Moscow’s annexation of Ukraine’s Crimea peninsula in 2014. Two-thirds of Poland’s weaponry dates from the Cold...