Sunday's mass shooting in Orlando, Florida — the worst in U.S. history — has refocused the U.S. presidential campaign on the threat of terrorism and especially how to stop so-called "lone wolf" attacks.
Presumptive Republican presidential nominee Donald Trump's previous proposal for a ban on Muslims also is getting fresh attention, rekindling fears among some Republicans that he will be a divisive general election candidate.
"Well, he's a volatile candidate," said John Fortier of the Bipartisan Policy Center in Washington. "And I think there have been moments where he has seemed to be tamed and become more a part of the party and made peace with the [Republican] establishment and then times where his comments really bring those problems up again. So, I don't think we are going to see that change with Donald Trump. He is who he is."
But some Republicans have cheered Trump's focus on calling out President Barack Obama and presumptive Democratic presidential nominee Hillary Clinton for refusing to use the term "radical Islamic terrorism." It has become a prime example of Trump's pledge to do away with political correctness.
On Monday,Trump spoke to supporters in Manchester, New Hampshire, where he seemed to offer a new version of his plan to temporarily ban non-American Muslims from entering the U.S.
"When I'm elected, I will suspend immigration from areas of the world where there is a proven history of terrorism against the United States, Europe or our allies," Trump told cheering supporters. "We cannot continue to allow thousands upon thousands of people to pour into our country, many of whom have the same thought process as this savage killer."
Debate over the term ‘radical Islamic terrorism’
Trump also wasted little time in accusing both the president and Clinton of having policies that have left the United States vulnerable to attack.
“Clinton wants to allow radical Islamic terrorists to pour into our country. They enslave women and they murder gays. I don't want them in our country,” he said.
FILE - Republican presidential candidate Donald Trump speaks at Saint Anselm College in Manchester, New Hampshire, June 13, 2016.
Trump also blasted both Obama and Clinton for a reluctance to utter the phrase "radical Islamic terrorism."
Clinton took issue with that in an interview on CNN, and said she is not afraid to use the term, but added that she does not want to "demonize…and declare war on an entire region." Clinton did use the phrase "radical jihadists" during a campaign appearance Monday in Cleveland, Ohio.
Clinton appeals for unity
Clinton opened her remarks in Cleveland with an appeal for national unity in the wake of the Orlando mass shooting. "This is a moment when all Americans need to stand together. No matter how many times we endure attacks like this, the horror never fades."
Clinton also spoke in favor of additional gun control measures, saying she would make lone wolf terrorists a priority and seemed to take issue with Trump's proposed Muslim ban. "We should be intensifying contacts in those communities, not scapegoating or isolating them," Clinton said to cheers from supporters.
President Obama also mentioned the need for additional gun control during a brief photo opportunity with reporters. "We make it very easy for individuals who are troubled or disturbed or who want to engage in violent acts to get very powerful weapons very quickly, and that's a problem," the president said after a briefing on the Orlando tragedy from top law enforcement officials in the administration.
President Barack Obama speaks about the massacre at an Orlando gay nightclub during a news conference at the White House in Washington, June 12, 2016.
Trump's challenge: please the base and seem presidential
Trump's reaction to the Orlando massacre and some of his previous seat-of-the-pants reactions to foreign policy issues have raised longstanding questions among analysts about whether he can shift from a primary contender to a national presidential candidate.
At the moment, Trump appears to be more concerned with solidifying his base within the Republican Party than making the political pivot to a more acceptable national candidate.
"He needs to hold on to that passionate 30 percent base that really loves him, partly because he says things that are unpopular with the rest of us," said Michael O'Hanlon of the Brookings Institution in a recent interview. "So, can he maintain that bridge between saying things that are unpopular and saying things that are presidential, or can he establish that connection? I don't know."
Recent polls give Clinton a big advantage in handling foreign policy issues, including surveys done by Quinnipiac University and Gallup. But a Quinnipiac survey done last month also gave Trump a slight edge on the question of which candidate would be tougher in dealing with the threat posed by Islamic State. Forty-nine percent of those asked said Trump, while 41 percent said Clinton.