Trump rally sparks extraordinary stretch in Republican race

The next morning, two of the candidates still fighting to defeat Trump, Florida Sen. Marco Rubio and Ohio Gov. John Kasich, said they were so disgusted by the chaos that they may not support the billionaire businessman if he clinches their party's nomination.

[...] when Trump appeared at another rally Saturday morning in Ohio, he was suddenly pulled midspeech into a protective ring of U.S. Secret Service agents charged with guarding his life after a man rushed the stage.

Taken together, they exposed anew the remarkable anxiety ripping through a country dealing with profound economic and demographic changes, as well as the anger roiling inside one of America's great political parties.

While not mentioning Trump by name, Republican National Committee Chairman Reince Priebus said in a statement Saturday that political leaders in both parties have a responsibility to ensure that the "discourse we engage in promotes the best of America."

Republican traditionalists kept whispering in private conversations about long-shot options for stopping Trump, either at a contested convention or by rallying around a potential third-party option.

Kasich, who has largely avoided tangling with Trump until now, said the real estate mogul has created a "toxic environment" that makes it "extremely difficult" to envision supporting him as the Republican nominee.

With his delegate lead mounting, there's little evidence that Trump sees any reason to alter an approach that includes encouraging his supporters to aggressively — and sometimes physically — stop protesters from interrupting his raucous rallies.

On Twitter, Trump said the man who rushed the stage at his Ohio event had ties to the Islamic State, citing a video that experts said could not possibly be linked to the radical militant group.