By Matthew Bigg
ATLANTA (Reuters) - Controversy over the execution in Georgia of a convicted murderer whose supporters say may be innocent has exposed a continuing divide in the United States over the death penalty.
Vocal support for capital punishment has long been viewed as a benchmark of toughness for politicians running for U.S. national or statewide office given public support for the so-called ultimate justice.
But advocates for Troy Davis say their coalition reached beyond civil rights leaders and opponents of the death penalty. It also included some Republican U.S. legal experts who support capital punishment but were troubled by the Davis case.
Davis was to die by lethal injection at 7 p.m. EDT (2300 GMT) on Wednesday at a prison in central Georgia for the murder in 1989 of police officer Mark MacPhail, who was shot dead outside a Burger King restaurant in Savannah, Georgia.
Davis' lawyers fought a long campaign to cast doubt on his guilt, arguing there was no physical evidence to tie him to the crime. They stressed that seven of nine witnesses on whose testimony he was convicted had since changed their story.
As the execution approached, the campaign to stop it grew. Nearly 1 million people signed an online petition, 2,000 attended a rally in Atlanta on Friday and there were various expressions of international concern.
"France urges the authorities and attorney of the state of Georgia to stop (Davis') execution, as there are still genuine and serious doubts as to his guilt," said a statement from the French Foreign Ministry on Wednesday.
"By executing a prisoner when there are serious doubts as to his guilt, (the authorities) would be making an irreparable error," it said. The secretary-general of the Council of Europe also called for the execution to be halted.
But despite publicity surrounding the case, there was little comment from U.S. politicians, a fact that death penalty watchers attributed to public support for capital punishment.
Polls show a substantial majority of Americans -- some 62 percent in 2010 -- support the death penalty though the figure has declined slowly over the last 15 years, according to Michael Dimock of the Pew Research Center in Washington.
In one sign of that support, Texas Governor Rick Perry was applauded for his hardline stance on the death penalty at a Republican presidential debate earlier this month. Texas has executed more people under Perry than any other state.
Those executed include Cameron Todd Willingham, who was put to death in 2004 for the murder by arson of his three children in a house fire. A story in the New Yorker magazine in 2009 argued that the evidence for arson in the case was flimsy.
The New York Times published an editorial on Tuesday calling the decision by Georgia's paroles board to deny clemency a "tragic miscarriage of justice." It also urged abolition of the death penalty in the United States, saying it was "unjust, discriminatory and incapable of being fixed."
Even so, Democrats are under particular pressure to speak tough on crime or risk appearing soft-headed to independent voters when they seek re-election, said James Coleman, a professor at Duke Law School who has defended capital cases.
"Politicians don't get involved in death cases. The only time mainstream politicians get involved with death cases is when they carry out executions," Coleman said.
For years, Davis' lawyers pushed for an evidentiary hearing to present their new witness testimony, and in 2009 the U.S. Supreme Court took the rare step of granting the request.
But a federal judge, after a two-day hearing in Savannah in 2010, ruled that the new evidence including the recantation testimony cast "minimal doubt" on his conviction.
Larry Thompson, U.S. deputy attorney general under President George W. Bush, said the standard for an execution should go beyond due process and attain the level of moral certainty about guilt. In this case, there can be no such certainty because of the conflicting witness testimony and lack of other evidence, he said in a view echoed by other legal experts.
"There are legal standards and the (Savannah) judge who is a very good lawyer applied the legal standards and concluded that he couldn't change the sentence," Thompson said.
"Given the moral certainty that you should have before you execute somebody I have concerns about this case," he said, adding: "I am not opposed to the death penalty and I'm not saying that this person was innocent.
There have been no polls conducted over the Davis case, but Jerry Luquire of the Georgia Christian Coalition argued that the execution should proceed because Davis had failed to prove his innocence in the only forum that counts -- a court.
Luquire said he guessed a majority of people in Georgia, and certainly in Columbus where members of MacPhail's family live, were quietly supportive of the execution.
Asked about the vocal campaign on Davis' behalf, he said: "Noise does not mean numbers."
(Editing by Tom Brown and Mohammad Zargham)