Conservative columnist Ann Coulter has called President Donald Trump the 'biggest wimp' in the history of the office following his concession on border funding to re-open the government.

Coulter, an immigration hawk and early Trump supporter, reacted with swift fury to Trump's announcement on Friday that he would reopen the government for three weeks without any commitment from Congress to fund a southern border wall.

'Good news for George Herbert Walker Bush: As of today, he is no longer the biggest wimp ever to serve as President of the United States,' Coulter wrote on Twitter.

Bush, who died in November aged 94, was widely ridiculed in office for going back on his 'read my lips' vow not to raise taxes.

Seeming bitter about some in Trump's inner circle, Coulter went on: 'Maybe the solution to the border crisis is not deporting 22 million illegals but one Jared Kushner.'

Ann Coulter, seen on Real Time on Friday night, lashed out at Trump for making a deal to reopen the government without securing any funding for a border wall

Couler declared that Trump backing down from his wall demand to end the shutdown made him an even bigger 'wimp' than George HW Bush, who famously reneged on a tax promise

Many have speculated that Coulter's December column calling Trump 'gutless,' which appeared to prompt him to unfollow her on Twitter, helped spur the President into undertaking the shutdown standoff in the first place.

'Yeah, crazy that I expect the President to keep the promise that he made every day for 18 months,' Coulter scoffed during a Friday appearance on HBO's Real Time with Bill Maher.

Coulter went on to downplay her influence on the President, saying that she is merely voicing the concerns of Trump's base.

'I promise you, the country would be run much better if I had a veto over what Donald Trump was doing,' she told Maher. 'It's the base, that's what happened.'

Coulter, addressing Maher's liberal audience, made the case that mass immigration is a policy supported by big business to suppress worker's wages.

'You know who wants it? The Koch brothers,' said Coulter, referring to the billionaire political activist family that has indeed supported laxer immigration policy. 'You're being played, to have everyone act like this is some sort of racist thing.'

'Yeah, crazy that I expect the President to keep the promise that he made every day for 18 months,' Coulter scoffed during a Friday appearance on HBO's Real Time with Bill Maher

Among the hardest core of Trump's base, many had expected the President to push forward with declaring a national emergency in order to build the wall, a proposal he had floated for weeks.

Thursday deal to reopen government came as a shock to this group and a potential blow to Trump's reelection chances.

Taking to Twitter, Trump defended his move and insisted that an emergency delcaration was still on the table if Democrats in Congress do not cut a deal to fund the border wall before the three-week deadline.

'I wish people would read or listen to my words on the Border Wall. This was in no way a concession. It was taking care of millions of people who were getting badly hurt by the Shutdown with the understanding that in 21 days, if no deal is done, it’s off to the races!' Trump wrote on Friday night.

He continued to battle base backlash on Saturday morning, writing: '21 days goes very quickly. Negotiations with Democrats will start immediately. Will not be easy to make a deal, both parties very dug in. The case for National Security has been greatly enhanced by what has been happening at the Border & through dialogue. We will build the Wall!'

In her interview with Maher on Friday, Coulter said that all of her concerns about Trump would be forgiven if the wall gets built.

'Just keep your promises and I'm right back in your camp,' she said.

Otherwise, speculation has circulated that Coulter might mount a primary campaign against Trump.

Asked about the possibility by Maher, Coulter joked: 'I'm against women working, so I can't.'