Donald Trump went where nobody could have expected even Donald Trump to go.
The real estate mogul and Republican presidential candidate, who's leading the field in several recent polls, lit into Senator John McCain of Arizona on Saturday when speaking to a conservative conference, even going after his legendary military service—and drawing instant condemnation from fellow candidates.
"He's not a war hero," Trump said in a question-and-answer session with pollster Frank Luntz. Then he altered his comment: "He's a war hero because he was captured. I like people that weren't captured, okay?"
The crowd responded with an awkward mix of shocked "oohs" 
and scattered applause. "Because he was captured, okay? Perhaps 
he's a war hero. But right now he's said some very bad things 
about a lot of people."
McCain spent more than five years in captivity as a prisoner 
of war in Vietnam, a brutal period during which he was tortured 
and faced solitary confinement, after his plane was shot down. 
His feud with Trump escalated last week after Trump rallied 
conservatives in Phoenix against illegal immigration, which 
McCain, who is running for reelection to the Senate in 2016, 
told New Yorker "fired up the crazies."
Trump retorted: "I know what a crazy is. I know all about crazies. 
These weren't crazy."
And that wasn't all Trump had to say about McCain. He
 attacked him for having "graduated last in his class" at the 
U.S. Naval Academy in Annapolis (McCain actually graduated 
Asked why he didn't serve in the Vietnam War, Trump responded 
that he had a bone spur, although he couldn't remember in 
which foot. "It's a long time ago. I had student deferments
 and ultimately had a medical deferment because of my
feet," he said.
Badgered by reporters at a news conference shortly after, 
Trump repeatedly refused to back down or apologize for his 
attack on McCain,  and even launched new missives. "I think
 John McCain has done very little for the veterans. I'm very 
disappointed in John McCain."
"If someone's a prisoner I would consider that person a war
hero. And we have a lot of war heroes that weren't prisoners 
also. And we should give them credit, too," he said.

Trump's fellow Republican candidates at the Ames, Iowa, forum,
 including Bobby Jindal, Lindsey Graham, and Rick Perry, 
quickly condemned the comments. 

"John McCain is an American hero. I have nothing but respect 
for his service to our country," Louisiana Governor Jindal said 
on Twitter. "After Donald Trump spends six years in a POW 
camp, he can weigh in on John McCain's service."

Former Florida Governor Jeb Bush, who was not at the 
conference, also tweeted. "Enough with the slanderous attacks."