Eric Garner death: Will US politicians get a prosecution?

Protests cropped up across the US in recent weeks after two grand juries failed to indict white police officers

Outside my Wall Street hotel last night, the taxi drivers were somewhat uncharacteristically turning business down.

"Go uptown? Forget it. They've closed the Westside Highway, and there are protests on Times Square."

"Brooklyn? Not a chance," said another driver. "The bridge is closed by demonstrators."

And so it was, in the city that doesn't sleep, the taxi drivers were going home early to bed.

Another week, another city, another dead black man, another grand jury and another white policeman not indicted. Oh, and another new chant.

Ten days ago in Ferguson, Missouri, it was "hands up don't shoot" after an unarmed black teenager was gunned down because according to some he had his arms up.

Demonstrators chanted "I can't breathe" in response to Eric Garner's death, precipitated by a police chokehold

In New York it was "I can't breathe, I can't breathe" after the horrible video was released of Eric Garner speaking his final words, as this 350lb giant of a man was held in an apparent chokehold by an NYPD officer.

Now if the defence of Darren Wilson, the police officer in Ferguson, tested the credulity of the African American community - that he felt his life was in danger from Michael Brown - what possible justification can be offered for Daniel Pantaleo's deadly grip on Eric Garner in Staten Island?

The mobile footage somehow contrives to show the utter banality of this death. This was no high-speed car chase, shoot-out death. This was an amiable-looking black guy on a summer's day, standing, talking to a bunch of policemen in shorts - in shorts for goodness sake! - refusing to comply with their orders but hardly posing a threat either.

Michael Brown, 18, was fatally shot in August

Anyway, no need to describe it further as I am sure that anyone reading this has already seen the video and its unhappy denouement.

But unlike in Ferguson where it seemed the federal government was not quite sure what to do initially - aside from appealing for calm - this time they were quick out of the blocks.

US Attorney General Eric Holder went on TV to announce that federal prosecutors would look at whether Mr Garner's civil rights had been infringed. In other words, Mr Pantaleo could still be prosecuted.

As a way of defusing tension, it was probably a very smart move. There was no repeat of the looting and rioting that came after the Michael Brown decision. Politically it was astute.

But will the federal government in Washington succeed in bringing an indictment where a Staten Island grand jury failed? That's the key question now

And the evidence is far from clear. I remember a senior British politician who in a previous life had been an eminent lawyer telling me you don't win a case just because something looks really, really bad.

While anyone looking at the video of the chokehold has probably a very clear view of how bad it was, that doesn't mean it's an open and shut case legally.

US Attorney General Eric Holder has launched an investigation into the circumstances of Eric Garner's death

There will be minute examination of the judgements made during the arrest. Did Mr Garner offer any resistance; how much pressure was applied in the neck hold? Was it unreasonable force? Was the inability to breathe because of Mr Garner's asthma rather than the force of the hold? Did Officer Pantaleo try to resuscitate him?

Will prosecutors be able to demonstrate wilfulness on the part of the officer, the high standard of intent required by the Supreme Court.

Of course it is being stressed by the justice department that the federal investigation would be fair, thorough and expeditious. But the will of the politicians is clear - they want a prosecution.

Otherwise the conclusion will be that a man can be choked to death on a street in New York in plain view, with video evidence - with no consequence.

And few would think that would be the criminal justice system's finest hour.