The preparations are well underway for the visit of Joe Biden to Ireland this week.
The US President will spend several days here, address the Joint Houses of the Oireachtas and make a public speech in Co Mayo.
Timothy Miller is a former Secret Service agent and has served with several US Presidents.
He told On The Record they treat every country the same.
"The Secret Service doesn't view any particular country as a lesser threat," he said.
"They're coming in game-ready; they will have had folks on the ground there advancing sites, making sure that they're working hand in hand with Irish officials - both on the intelligence side and on the law enforcement side.
"The Secret Service's mission is focused on protection, which means they're preparing for it not to happen.
"They're not reactive in nature, they want to make sure that all the i's are dotted and the t's are crossed.
"Wherever they go, they're expecting the worst: that's the nature of the Secret Service.
"Fortunately for them they're highly-trained professionals, and for most events they go off without a hitch".
Mr Miller said what people see is only a fraction of what goes on.
"The Secret Service was formed back in 1865 during the American Civil War to deal with the counterfeit currency issue," he said.
"Their mission was totally secret back then.
"In 1901, when President McKinley was assassinated, the Secret Service assumed protective responsibilities.
"But don't fool yourself: what you see is only a portion of the efforts that the Secret Service undertakes".
Mr Miller said everything they do is in cooperation with local authorities.
"We recognised - I've been all over the world with protectees - that you can't do what you need to do without the hand-in-glove relationship with, in this case, the Irish officials," he said.
"The Secret Service doesn't change its protocols just because we're going to this country or the other.
"Most organisations and countries that we go to, they're very respectful of the fact that the Secret Service has a very serious mission - to protect the leader of the free world - and they're going to be very diligent in doing it.
"That's completely based on a cooperative effort between the two.
"The Secret Service is very mindful; we don't go into foreign countries and take over, we coordinate with those agencies to make sure that protectees are safe".
Mr Miller said if a president meets people up close agents are "exceptionally nervous."
"It's not just about trying to look cool - you're mentally in the game trying to identify those indicators that someone is potentially a threat," he said.
"Obviously when you go into unscreened crowds, that's problematic.
"We try as best we can to work with the protectees to say, 'If we can do this Mr President'.
"Obviously at the end of the day, they're human beings - they get to choose and we respond accordingly," he added.
Listen back to the full interview below: