George Zimmerman, who shot unarmed teenager Trayvon Martin, appears in court today to face charges of second degree murder. Now his lawyer says he is concerned about getting a fair trial.

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It has taken more than 40 days to reach this point: 45 days, to be exact, since neighbourhood watch volunteer George Zimmerman shot and killed Trayvon Martin as he walked through a gated community in the Florida town of Sanford. 45 days since the local police chief decided not to arrest Zimmerman because it might violate his human rights.

Last night, after Florida's special prosecutor, Angela Corey, announced that Zimmerman was now in custody and would face a charge of second degree murder, Trayvon Martin's mother Sabrina Fulton was dignified despite her grief. "We simply wanted an arrest," she said, while the teenager's father Tracy Martin added: "We will continue to walk by faith, we will continue to hold hands on this journey. White, black, Hispanic, Latino... we will march until the right thing is done."

George Zimmerman's new lawyer, Mark O'Mara, who is no stranger to appearing in the public eye, expressed his fears that a case which has sparked such a national firestorm about race and crime, could ever allow his client a fair hearing. "He is a client who has a lot of hatred focused on him," he said. "I'm hoping the hatred settles down."

Angela Corey has already taken pains to stress that her decision to prosecute had nothing to do with the public pressure for charges to be bought, yet there is so much evidence and speculation out there, it seems a tough challenge to find a jury that can look at the facts afresh. Since the shooting happened, you could have listened to the original 911 call in full - or a deliberately edited version, for which heads have rolled at one TV network.

ALEC and the Trayvon Martin affair

Liberal groups here in the States have been targeting the American Legislative Exchange Council over their involvement in controversial voter ID and self-defence laws, writes Carl Dinnen. The Trayvon Martin affair gave their campaign massive impetus and big corporations have been pulling out of ALEC.

Pepsi had already left, Coke , McDonalds and Kraft followed recently. Now I’ve learned that Mars are also quitting ALEC. Until today it wasn’t even clear that they were a member, although we knew they’d been at last year’s ALEC conference. In their statement Mars – like the others – did not reference the recent controversies.

Through no fault of their own Mars are linked to the Trayvon Martin case. He had gone out to buy a bag of their Skittles and the brightly coloured packets have become a potent symbol for campaigners on his behalf. An increase in sales has even been reported.

Mars were at pains to point out that, although members of ALEC, they were not involved in its policy making. Like the other big corporations their interest is most likely to lie in business-related legislation. But ALEC’s involvement in controversial right-leaning laws has exposed its big brand backers to the possibility of a consumer backlash, one they are not willing to risk.

Mars, Incorporated sent this statement to Channel 4 News about its ALEC membership -

"Earlier this year, Mars, Incorporated reviewed all of its trade associations and sponsorships and decided not to renew the ALEC membership in 2012. In the past, we attended the ALEC annual meeting to create awareness of our positive economic impact and job creation in the communities where we operate. At no point was Mars ever involved in ALEC’s policymaking or Private Enterprise Board."

Evidence made public

CCTV images of Zimmerman being taken into the local police station have been released, with much comment about whether he showed any sign of injuries or not, a key point in the case. It is now common knowledge that Zimmerman was allowed to keep his gun and go home. His clothes were not confiscated for forensic examination. Any injuries he might have had were not documented.

We simply wanted an arrest. Sabrina Fulton, Trayvon Martin's mother

There has also been endless discussion of Florida's "stand your ground" law, which meant Zimmerman was not arrested in the first place. Inevitably, that debate was laced through with that of race, dividing the country along fissures of race, of class, of generations. If Zimmerman had been black and his victim white, would he have been allowed to walk home free?

One veterans' activist, Jon Stoltz, even compared the Florida law to the rules of engagement imposed on US troops in Afghanistan or Iraq, saying it "gives more leeway to shooters than our own military gives to soldiers in war".

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Millions on the march

And thus was a massive public campaign created, in Trayvon Martin's name. Tens of thousands of people marched around the country, bearing his image on placards and T-shirts. Thousands more, from political leaders and sporting stars, to high-school students, donned hoods like the one Trayvon had been wearing when he died. More than 2 million signed a petition urging charges to be brought. Others defended Zimmerman, who was in hiding, for fear of his life.

We don't want anyone high-fiving tonight. There's no victory here. There are no winners here. Al Sharpton, civil rights leader

Now he has been charged, the focus is turning to justice. The civil rights leader Al Sharpton, who has been a key supporter of the Martin family's campaign, insisted that no-one was in the business of revenge. "He deserves a fair trial. We don't want anyone high-fiving tonight. There's no victory here. There are no winners here."

The US Justice Department is conducting its own independent investigation into the shooting, sending officials to meet the Martin family, members of the local community and Sanford authorities, along with the FBI. The attorney general, Eric Holder, acknowledged: "Many of you are greatly - and rightly - concerned" about Trayvon's death, describing the 17-year-old as "a young man whose future has been lost to the ages."

Resisting pressure

In cases where public anger has reached such a crescendo, there will undoubtedly be enormous pressure for a conviction, pressure which the authorities insist they are at pains to resist. When Zimmerman appears in court today, his lawyer will be asking for bail. If that fails, as expected, Florida law means the defence can try to prove by a "preponderance of evidence", a relatively low legal standard, that he acted in self-defence and not out of hatred or ill will.

Justice needs to be seen to be done, even if it is 45 days after the fact.

But the idea that a judge would be willing to throw out the case at a pre-trial hearing and not let it be heard by a full jury is unlikely in the extreme. Justice needs to be seen to be done, even if it is 45 days after the fact. Zimmerman faces a highly serious charge, with a maximum term of life in prison: anyone accused of murder in the second degree would be scared, his lawyer said.

It is a high bar for prosecutors: but a young man is dead, and has no option of life, behind bars or anywhere else. After all, there has surely been too much heartbreak, too much prejudice already on ugly display, not to let fairness have its day in court.

Felicity Spector writes about US affairs for Channel 4 News