What will happen when Donald Trump is arrested?

Donald Trump has been indicted by a New York grand jury, the district attorney has confirmed.

But what can the former president expect when he is arrested, and can he expect to be treated differently to the average criminal suspect in New York?

Is Donald Trump about to be arrested? Why?

Manhattan District Attorney Alvin Bragg has confirmed Trump has been indicted, and an arrest will be pending.

Once a decision has been made to arrest someone, law enforcement normally acts immediately.

A grand jury in New York has voted on criminal charges for Trump. Those charges have not yet been revealed.

While the details have not been made official, this investigation relates to hush money paid to adult film star Stormy Daniels.

Daniels was given $US130,000 ($194,000) during the 2016 presidential campaign to keep quiet about an alleged affair she had with Trump.

The grand jury investigation centres around whether Trump concealed the hush money as something else.

If he presented it in his books as a legal or a business expense, he could face fraud charges.

He could face a maximum of four years in jail if found guilty.

READ MORE: Why a Trump indictment would have huge implications

What is an indictment?

An indictment is a formal notice that a person is believed to have committed a crime.

In New York, the indictment includes all the felony charges that a person will go on trial for.

An indictment is different from an arrest, but if Trump is indicted, it means he will be arrested.

How will an arrest take place?

A SWAT-style raid on Trump's country club in Mar-a-Lago is not going to happen, and we won't see him kicking and screaming as they drag him into a squad car.

An arrest will need to take place with the consultation of the Secret Service agents tasked to protect him.

This is unprecedented in US history, because nobody with a Secret Service detail has ever been arrested.

As a former president, Trump is entitled to Secret Service protection.

But that likely won't mean they will be allowed to follow him into court or frisk the judge at his bail hearing.

The most likely course of action will be the Manhattan district attorney's office will contact his lawyers, and Trump will fly up to New York to surrender.

READ MORE: Trump says he won't drop out of presidential race if he's indicted

What will happen after Trump is arrested?

There's an indecorous tradition in New York law enforcement called the "perp walk", where high-profile suspects are paraded in front of cameras.

In a perp walk, handcuffed suspects are walked slowly from a police car into the courthouse, while news photographers jostle to snap photos of them.

The New York Times is reporting that Trump is considering whether to smile for the cameras if he is put through a perp walk.

But both the New York Daily News and the New York Post cite police sources saying Trump won't be put through a perp walk.

But if he is indicted, Trump will be booked, most likely at the Manhattan district attorney's office.

That means he will be fingerprinted, have his mugshot taken and be read his Miranda rights ("You have the right to remain silent...").

Mugshots in New York state are not allowed to be released, but it is very possible it gets leaked.

Whether Trump is handcuffed will be up to the district attorney's office.

READ MORE: Judge lets 'Access Hollywood' tape into Trump rape trial

When will Trump face court?

Trump will likely not face any time behind bars before facing court for his bail hearing.

He will likely be taken directly from the district attorney's office to court, where his lawyers will ask for him to be released under his own recognisance.

It is almost certain Trump will be immediately released.

Under New York's recent bail laws, a suspect is required to be released without bail unless they have committed a violent crime or are considered a flight risk.

Trump may be required to surrender his passport and could be prevented from leaving the state.

When would Trump face trial?

A trial could be months away, thanks in no small part to Trump's fame.

Jury selection would be an immense headache in the case.

Finding 12 New Yorkers who don't already have a strong opinion about Donald Trump is going to be very difficult.

Can Trump be charged if he is running for president?

He absolutely can.

Even if he were still the president, Trump could be arrested, indicted, tried, convicted and imprisoned if guilty of any crime.

While federal guidelines advise law enforcement against prosecuting politicians too close to election day, New York prosecutors are not bound by this rule.

The only criteria for running for president is that a person needs to be older than 35 and a "natural born citizen".

Trump could still be elected president even if behind bars, though he would still need to serve his term in jail while serving his term in the Oval Office.

While no former president has ever been arrested, one sitting president has.

Ulysses S. Grant was arrested in 1872 for speeding on his horse and buggy as he raced through Washington.

READ MORE: Pence says Trump 'endangered my family' on January 6

Will there be protests if Trump is arrested?

Very possibly, but the most recent demonstration in New York was a dud.

A protest outside Manhattan Criminal Court on Tuesday morning only attracted five Trump supporters and a few dozen anti-Trump counter-protesters.

Despite this, all 35,000 officers of the New York Police Department have been ordered to be ready to mobilise in full uniform at a moment's notice.

Heavy fencing was set up around the courthouse as the grand jury made its decision.

READ MORE: Trump calls for protests over arrest

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