U.S. Republican convention begins with stress on security issues

By Ginger Gibson and Steve Holland CLEVELAND (Reuters) - Republicans meeting this week to anoint Donald Trump as their presidential candidate will try to sell the combative businessman to voters as a strong leader who can shield America from the threats of violent crime and Islamist militants. Trump allies will promote what he bills as a tough line on law and order and national security in speeches later in the day. The theme for the first day of the meeting had already been set as "Make America