Orlando shootings: Would Trump’s national security plan work?
Republican presidential candidate Donald Trump says US counter-terrorism efforts are "terrible" - and that he has a way to make the system better. Is he right? And are his proposals really new?
On Monday, Trump delivered remarks about the shooting deaths of 49 men and women in an Orlando, Florida, club - the worst mass shooting in US history. He used the speech to slam the Obama administration's counter-terrorism efforts.
"We're importing radical Islamic terrorism into the West through a failed immigration system and through an intelligence community held back by our president," Trump said.
He's also said: "We have terrible intelligence gathering right now."
Trump reiterated his proposal for a ban on Muslims - and said that he'd implement a way to "perfectly screen" everyone.
However, Trump offered no details about what that "perfect" screen would be.
But the presumptive Republican presidential nominee has repeatedly compared recent events to the attacks of 11 September 2001.
Law enforcement experts say that much of what Trump proposes sounds similar to the reactive measures that were implemented back when George W Bush's administration poured additional resources and powers into US intelligence agencies.
However, many of those programmes and surveillance strategies were eventually deemed imperfect. Civil libertarians fought for years to have them dismantled.
"After a horrible event, there's an impulse to do something - rather than to examine what went wrong and to develop effective policies," said New York University's Michael German, a former FBI undercover agent.
"[After 9/11,] Americans made a bad deal. They were asked to sacrifice their privacy to make the country safe. But it doesn't make the country any safer. In fact it makes the country less safe because security resources are directed away from real threats."
On Monday, Trump repeated his promise to give law enforcement more "tools" - though he was not specific about what those tools should be.
Jeffrey Ringel, who's worked as an FBI supervisor on a joint terrorism task force, does have one thing on his wish list - the ability to force technology companies like Apple to programme a "key" for law enforcement to get into encrypted products, like the iPhone. Currently, newer iPhones delete their data if the wrong password is entered repeatedly.
In the past, Trump ripped into Apple for refusing to help officials in their investigation of the San Bernardino gunman, Syed Rizwan Farook, who gunned down 14 people in 2015. Federal investigators wanted Apple to break into Farook's iPhone, but Apple executives refused.
"Who do they think they are?" Trump said at the time.
Ringel complains that phone encryption has hampered investigations in the past.
"That does prohibit us from tracking where people are," he says.
Other law enforcement experts say that in terms of resources, the country's intelligence-gathering agencies have what they need to ferret out plots.
"We spend a fortune on intelligence," said George Washington University's Stephen Saltzburg, a former deputy assistant attorney general in the US Department of Justice. "The tools are there."
However, managing the number of terrorism cases is a real challenge. Currently, the FBI has 900 open investigations of people, "an unprecedented number", said the Rand Corporation's Kim Cragin. There are hundreds, if not thousands, more investigations at the state level, in preliminary stages.
Agents are "drowning in information", according to NYU's German. As a result, they don't catch things they should - or sometimes over-react.
"The FBI's approach now is to cover every threat," he said. "They pull false alarms."
Trump also seemed to indicate he would step up surveillance on Muslim communities. That echoes his previously stated desire to begin "surveillance of certain mosques".
Amnesty International's Naureen Shah says it's not clear how his proposals would help.
"There's no evidence that even if the FBI were to put the entire Muslim population under surveillance, that it would prevent another attack," she says.
In fact, the US government launched aggressive efforts to surveil its own citizens after 9/11 - and the results were not always productive.
Weeks after 9/11, Bush signed the Patriot Act into law, giving broad authority to law enforcement to conduct surveillance operations on US citizens. At the National Security Agency (NSA), officials embarked on a massive effort to collect phone records of American citizens.
But in the end, the programme was not as effective as its creators had hoped.
"It was never once used to stop a terrorist plot," says German.
When NSA contractor and whistleblower Edward Snowden revealed that the government's most aggressive surveillance programmes were sometimes focused on Muslims, many Americans were outraged.
Last year, Obama signed a new version of the Patriot Act, the USA Freedom Act, which ended the government's bulk collection of phone data and some (but not all) of the government's invasive practises.
There was similar fallout after the New York Police Department conducted widespread surveillance operations on Muslim communities in New York City.
The officers referred to certain mosques as "terrorism enterprises" and, according to New York Times reports, spied on worshippers, keeping detailed records of where they "ate, prayed and shopped".
The department was repeatedly sued for discrimination and the unit was ultimately disbanded. City officials never said they did anything wrong, but agreed to appoint a lawyer to work inside the police department and monitor their activities.
"[After 9/11,] there was more of a willingness to give intelligence a freer hand. There's been a pushback," says Jamil Jaffer, a former adviser on the US senate committee on foreign relations.
The one thing that the US has never tried is Trump's "total and complete shutdown" of borders to Muslims.
"I will suspend immigration from areas of the world when there is a proven history of terrorism against the United States, Europe or our allies, until we understand how to end these threats," he reiterated Monday.
It's hard to imagine how a ban would work in real life, and whether Trump would change laws on tourism, immigration laws, asylum laws - or all of the above.
"I honestly don't know," says Shamila Chaudhary, a former Obama administration official. "It's very sensationalistic rhetoric."
Trump also says authorities can't "effectively check backgrounds" of individuals who come to the US, but Columbia University's Daniel Richman, a former federal prosecutor, said that the current background checks are "rigorous". He adds that even under the best of circumstances, it's hard to screen people who are coming from places like war-torn Syria.
"There's no way to be perfect on this," he said.
In response to Trump's remarks, Obama said in a speech on Tuesday that not only are the Republican candidate's remarks offensive, his policies would actually be counter-productive to America's anti-terrorism efforts.
"If we fall into the trap of painting all Muslims with a broad brush and imply that we are at war with an entire religion, then we are doing the terrorists work for them," Obama said.