Unlike two other security companies operating in Afghanistan and Iraq, Blackwater has said it designates its workers contractors, not employees, because it is a "model that works" and because its guards prefer the "flexibility" of the contractor relationship.

The arrangement has, according to Mr Waxman, wrongly allowed Blackwater to avoid paying social security and Medicare taxes, as well as federal income and unemployment tax - or $32m (£16m) in taxes from May 2006 to March 2007.

The IRS ruling was issued after a single security guard approached the tax authority after a dispute over back pay and other compensation. Although the ruling, which is based on Blackwater exercising control over its worker, applied only to the individual, the IRS alerted Blackwater that it could apply to others.

Blackwater, which has classified 604 security guards as contractors, agreed a settlement with the employee after the ruling. That included a confidentiality agreement that prohibited the employee from contacting "any politician" or "public official" about its details.

"It is deplorable that a company that depends on federal tax dollars for 90 per cent of its business would even contemplate forbidding an employee to report corporate wrongdoing to Congress," Mr Waxman said in a letter to Erik Prince, Blackwater chairman and CEO.

He further alleged that the confidentiality agreement was "particularly suspect" because it was signed by Blackwater general counsel Andrew Howell just as Mr Waxman's committee was stepping up its investigation into Blackwater's activities.

Blackwater said that Mr Waxman's assertions were "incorrect" and took issue with his use of the IRS decision, against which the company has appealed.

The company said the IRS had not made a final determination on the employee and the Small Business Administration had decided Blackwater security contractors were not employees.

Gary Medrano, of Woodbridge, Va., filed the lawsuit on Monday in U.S. District Court for the Southern District of Illinois, saying his 2000 Ford F-150 XLT caught fire in October 2006 because of problems with the cruise control switch. The suit seeks class-action certification.

The 10-count complaint does not seek a specific amount of damages, but is asking for both compensatory and punitive damages.

The Dearborn, Mich.-based automaker has recalled more than 10 million vehicles since 1999 because of engine fires linked to the cruise control systems in trucks, sport utility vehicles and vans.

Ford spokeswoman Kristen Kinley said the company was reviewing the lawsuit, but could not comment on the case. A message seeking comment was left Friday with St. Louis attorney Jeffrey J. Lowe, who is representing Medrano.

Medrano said the fire in his pickup truck was extinguished by the fire department, but the vehicle and its contents were left completely unsalvageable.

The lawsuit said the National Highway Traffic Safety Administration has reported at least 218 similar fires from the cruise control deactivation switches. By June 2005, NHTSA had confirmed at least 65 fires were caused by the failure of the switch system.

Recent decisions by judges and elected officials have made clear that most executions will not proceed until the Supreme Court rules in a challenge by two death row inmates to the lethal injection procedures used by Kentucky. The inmates say Kentucky's method creates the risk of pain severe enough to be cruel and unusual punishment, banned by the Eighth Amendment.

Similar procedures are used by Texas, the far-and-away leader in lethal injections, and the 16 other states that have executed prisoners in the past two years.

It is clear the high court will not go so far as to outlaw the use of lethal injections. That issue is not even before the court in the Kentucky case.

Rather, the justices could decide whether Kentucky's procedures violate the Constitution and what standard the courts should use to evaluate the risk a prisoner will feel pain as he is put to death.

No matter how the court rules, it appears there will be few, if any, prisoners executed before the court rules, probably by late June.

"We're probably looking at delaying executions, not preventing them," said Ronald Tabak, a New York-based lawyer with the Skadden Arps firm who has represented death row inmates.

Tabak said states with the death penalty now have a chance to review capital punishment procedures. The American Bar Association has for the past 10 years called for such a freeze and review.

"The ABA's position is unless you have fair practices, executions should not resume," said Tabak, who has worked with the lawyers' organization on this issue.

But Douglas Berman, a sentencing expert at the Ohio State University law school, said the possibility exists for more dramatic action.

"The abolitionists will say if we have no executions for six months to a year, and the universe is not imploding and murder rates are not going through the roof ... it becomes easier to say, 'Why do we even need the death penalty, let's just get rid of it,'" Berman said.

"Texas and other high-execution states aren't going to get there anytime soon, but the argument against capital punishment gets even more force in those states squeamish about the death penalty in the first instance," Berman said.

Questions about the administration of lethal injections are only part of the equation.

Death-penalty opponents also have pointed to doubts about the competence of some court-appointed defense lawyers and the rise in the number of exonerations through DNA evidence of people already convicted of crimes.

Polling has shown that the public increasingly believes that life in prison without parole will keep the worst offenders off the streets. A recent Associated Presss-Ipsos poll that asked what method of punishment people prefer for murderers found only a slight preference for the death penalty over life in prison — 52 percent to 46 percent.

"There is a deeper societal appreciation for life without the possibility of parole. Ten to 15 years ago, no one thought they meant it," Berman said.

At the same time, there have been several studies, challenged by the anti-death penalty camp, that have shown a deterrent effect in the use of capital punishment. Also, public support for executions remains high. More than two-thirds of those polled favor the death penalty for murderers when the question does not include other possible punishments.

Then there is the example of the last time the country went without executions for an extended period. There were no executions from June 1967 to January 1977.

The Supreme Court in 1972 struck down 40 state death penalty laws, but did not ban capital punishment as cruel and unusual.

Some justices at the time thought their decision in Furman v. Georgia would bring an end to the death penalty.

By 1976, though, in the midst of a "law-and-order" backlash to the court's decisions in favor of the rights of criminal defendants, elected officials in 35 states had adopted laws to comply with the death penalty ruling.

A more conservative court upheld some of those laws, and a half-year later executions resumed.

A senior official from the Construction, Forestry, Mining and Energy Union has appeared in the Perth Magistrates court to face a charge of trespass.

It is alleged the assistant secretary of the union, Joe McDonald, entered the Lakeside Shopping Centre building site at Joondalup in February and refused to leave when asked by site official.

The court has heard Mr McDonald had his state and federal tickets to enter building sites revoked in July last year.

Today his lawyer argued Mr McDonald was on the site lawfully and left within a reasonable time after he was requested to do so.

The Magistrate, Joe Randazzo, reserved his judgement until Thursday so he could consider relevant case law.

The Brooklyn man pleaded guilty to a violation after spending a night in jail, but he later appealed. Courts have upheld his arrest so far.

His lawyer, Nancy E. Little, said Wednesday there was no legal justification for arresting Jones for simply standing on the street.

"You need something more," she said. "You need to be being verbally abusive, or really blocking lots of people, or lying down on the sidewalk."

But assistant Manhattan district attorney Paula Rose-Stark said the disorderly conduct arrest was warranted, noting that Jones' behavior stood out "amid the inevitable hustle and bustle of Times Square."

Prosecutors' arguments drew several questions Wednesday from judges — including Chief Judge Judith Kaye, who wondered aloud how bustling Times Square was when Jones was arrested around 2 a.m.