According to a number of polls, Donald Trump has some of the worst approval ratings of any US president ever .

But here we are, 100 days in, still going strong(ish).

Many experts have been predicting that his term will be cut short, either by a resignation or impeachment.

In the history of the US, no president has ever been successfully impeached and removed from the White House. Both Bill Clinton and Andrew Johnson had been in the firing line, but both were acquitted by the Senate. While Richard Nixon left under his own steam.

However, Donald Trump presents a new era of presidencies, and experts have been pointing out that he may well be the first to be impeached.

Here are five experts in various fields, who have come out and said that Donald Trump won’t last very long.

1. Historian and Professor, Ronald L Feinman

The American history professor said that Trump, who is 70, would stay in the job "between the 31 days of William Henry Harrison in 1841" and the "199 days of James Garfield".

Feinman argues that it will be Vice President Mike Pence who will eventually challenge Trump for the presidency.

In a blog post about it, Feinman writes:

Pence knows how to play “hard ball” and it is clear by his demeanor and body language that he is often uncomfortable with Trump’s freewheeling and careless behaviour. An investigation into the Flynn matter will develop, with Speaker of the House Paul Ryan and Senate Majority Leader Mitch McConnell promoting it... As the FBI investigates this situation further, which would be expected to occur as a normal procedure after such a high level and immediate scandal, the earliest ever in any Presidential term (25 days), there will be calls for Trump to resign or be impeached.

2. Political historian, Allan J Lichtman

Allan J Lichtman, dubbed 'prediction professor' for correctly theorising that Donald Trump will win the US presidential elections, has come forward with another chilling predication.

Speaking to The Independent earlier this month, he predicted that Trump is to be impeached, and what’s more, that there is a 50 per cent chance that it will happen before the mid-term elections of 2018.

He said:

There is a Russian sword of Damocles hanging over him [Donald Trump].

There are several reasons he may be impeached, including alleged “crimes against humanity” for withdrawing the US from the effort to stop climate change. Additionally, he points to two rules – the emoluments clause of the US constitute which prohibits him from accepting gifts from foreign powers, and the second is a law that prevents public officials from benefiting from insider knowledge.

Lichtman says that Trump hasn’t yet given the money that foreign officials may have paid to him for staying at his hotels abroad.

3. Anthropologist, Hugh Gusterson

Similarly to Ronald Feinman, anthropologist Hugh Gusterson believes that Trump will deposed by his own party.

In a column for Bulletin of the Atomic Sciences, he writes:

I expect President Trump to be deposed in a Republican house coup. He will then have been a vehicle for the election of President Pence.

4. Professor of politics, Angelia Wilson

Professor Angelia Wilson, from the University of Manchester told The Independent that it is “highly likely” that the US president will be “impeached in the first 12 to 18 months”.

Wilson argues that a number of subjects could ignite the fire, including the Russia dossier. She says that the scandals which have been trailing Donald Trump are likely to become a “liability” for the Republican Party.

At some point they will need to distance themselves from him in order to solidify re-election for the House.

5. Harvard Law School professor Noah Feldman

Harvard Law professor Noah Feldman doesn’t think it will be Trump’s scandals that will be his undoing, but rather the “subtle, careful, slow undercutting of press freedom”.

Under Article II, Section 4 of the Constitution, a president can be impeached for “treason, bribery and other high crimes and misdemeanours.”

This, according to constitutional lawyer and historian Kevin R C Gutzman, can include abuse of power, under which manipulation of the press can fall.

In a podcast for Slate, Feldman says: