Republican presidential candidates Donald Trump and Jeb Bush clashed angrily over the Iraq war, the Bush family and Trump's business dealings at an acrimonious debate that underscored the importance of South Carolina's primary in a week.With the Republican candidates increasingly anxious for a good showing in the first primary in the American South on Feb. 20, fights between Trump and Bush dominated the two-hour debate hosted by CBS. "George Bush made a mistake," Trump thundered. "We all make mistakes. But that one was a beauty ... They lied! They said there were weapons of mass destruction. And there were none."Many in the crowd booed Trump and the Republican front-runner dismissed them as "lobbyists and special interests" who supported Jeb Bush, the former Florida governor.