Secret Service agents guard Republican presidential candidate, businessman Donald Trump, on the stage after a man tried to breach the security buffer at his campaign event at the Wright Brothers Aero Hangar Saturday, March 12, 2016, in Vandalia, Ohio. (AP Photo/Kiichiro Sato)

GOP rivals questioning whether they’d back Trump as nominee

Republican presidential candidates Marco Rubio and John Kasich suggested Saturday they may not support Donald Trump if he becomes the GOP nominee, as violence at the front-runner’s rallies deepened the party’s chaotic chasm.