LAS VEGAS - Republican front-runner Donald Trump sharply clashed with challenger Jeb Bush in a national security debate on Tuesday but escaped any severe criticism from his other rivals, who were ...

Jeb Bush speaks during the CNN Republican presidential debate at the Venetian Hotel & Casino on Tuesday, Dec. 15, 2015, in Las Vegas. (AP Photo/John Locher) Jeb Bush speaks during the CNN Republican ...

Jeb Bush, right, and Donald Trump at the Republican presidential debate hosted by Fox News on Aug. 6, in Cleveland. After failing to directly confront Trump in the first debate, Bush and his aides are ...

For some time now, Donald Trump has been attacking Jeb Bush, mostly in media appearances or on Twitter. But, over the last few weeks, Trump has been using Instagram in his fight. Trump has been ...