The Dirksen Senate Office Building reopened Monday morning, nearly a week after three US Senate buildings were closed by an apparent terrorist attack using the biological poison ricin. The Russell and Hart buildings reopened Friday.

The powder later identified as ricin was discovered February 2 in Dirksen Room 464, the mailroom attached to the offices of Senate Majority Leader William Frist. The mailroom and two adjacent rooms remained shut, sealed with plywood as decontamination and investigation of the attack continued.

According to press reports Monday, investigators from the Capitol Hill police and the FBI were making little progress because the quantity of powder was too small to conduct tests that would determine the size or potency of the ricin particles.

The main line of investigation is reportedly an effort to conduct DNA testing to determine the geographic origin of the castor bean plant from which the ricin is derived. The plant grows wild in a number of Southern states, including Georgia and South Carolina, and it is cultivated commercially on a small scale in Texas.

Because it is a poison rather than a germ or virus, ricin is not suitable for use as a weapon of mass killing, but it is highly lethal when injected or inhaled. There was no indication that anyone in the mailroom or elsewhere in the Senate building was affected by the release of the toxin, however.

Another envelope containing ricin, and addressed to the federal Department of Transportation, was found last October 15 at a mail facility in Greenville, South Carolina. That envelope was clearly marked “Caution, ricin poison enclosed in a sealed container. Do not open without proper protection.” A typewritten letter inside identified the sender as the owner of a fleet of tanker trucks who was opposed to new federal regulations requiring more rest hours for truck drivers.

After the Senate buildings shut down, the Bush administration revealed that there had a third such ricin-laced letter, this one addressed to the White House, intercepted by the Secret Service November 6. That incident was never made public and no notification was provided to the Capitol or other buildings which were likely targets for a similar attack.

The envelope addressed to the White House was labeled like the first envelope to the DOT, and also contained a letter denouncing the federal trucking regulations. Both letters were signed by “Fallen Angel,” and both warned that the writer had access to castor beans and would use ricin to poison food supplies if the rules were not canceled. The new federal rules took effect January 4.

The concealment of the letter to the White House raises a number of political issues. It reveals a significant double standard, already evident in the anthrax attacks on Congress in 2001. While the Bush administration incessantly trumpets the danger of terrorist attacks by Al Qaeda, in order to terrify the public and mobilize support for its military operations in the Middle East and Central Asia, it is curiously indifferent to threats of violence whose source is domestic—and whose target is the US Congress.

In the course of the past three months, the Bush administration has repeatedly disrupted international air traffic, hyping the threat of a repetition of the September 11 terrorist attacks, and issuing an orange alert during the Christmas and New Year travel period. At least 18 international flights were cancelled and tens of thousands of air travelers inconvenienced, but the US government provided no concrete characterization of the actual threat and offered no evidence to back up its increasingly sensationalized warnings. But during this same period, from November 6 to February 4, the Bush administration concealed the fact that an envelope laced with a deadly poison had been mailed to the White House.

Several members of Congress criticized the administration for failing to notify them of this attack, so that measures could have been taken to protect the Capitol. Edward J. Markey, Democrat from Massachusetts, a member of the House Select Committee on Homeland Security, told the Washington Post, “It is appalling that the lives of innocent people were put at risk when the precautions we are now taking against ricin could have been implemented on the basis of what the Bush administration apparently knew three months ago.”

Senate Minority Leader Tom Daschle of South Dakota, one of the targets of the anthrax mailing in 2001, said congressmen and senators of both parties were “very frustrated about the way that whole matter was handled. There’s no reason why information that vital should be withheld.... It affects our own ability to cope with circumstances similar to those, here on the Hill.”

All documented cases in the United States of the use of ricin as a weapon have involved fascist and white supremacist groups that have political links to the right-wing of the Republican Party—a fact about which the US media and the Bush administration have been largely silent.

In 1993, according to one report, an American white supremacist, Thomas Lavy, was found carrying a container of ricin as he sought to cross the Canadian border from Alaska. He was released, but arrested two years later by the FBI, whose agents found castor beans in Lavy’s cabin in Arkansas. He later committed suicide in jail. In 1995, four members of a group of anti-tax militants in Minnesota were convicted of plotting to kill a federal marshal using ricin.

The political motivation for the ricin attack—assuming that the envelope to Congress was sent by the same individual or group who sent the first two letters—also suggests a connection to the ultra-right. Attacks on federal regulation of business are a staple of right-wing political demagogy.

As in the anthrax case, there may be a link to the US military biological weapons program as well. The Army patented a method of making weapons-grade ricin in 1962, and the recipe is still circulating on the Internet.

Such connections make a leading right-wing apologist for the Bush administration, the Wall Street Journal editorial page, extremely nervous. The Journal published an editorial February 4, written while the Senate office buildings were still shut down and before any information was available on the previous mailing to the White House, suggesting an Al Qaeda connection.

“Foreign sources or their US agents shouldn’t be ruled out prematurely,” the Journal argued. “The links between ricin and Iraq and Afghanistan certainly deserve deeper examination. It’s hardly a leap of imagination to think that Al Qaeda or other terrorist organizations are looking to strike the US once again.”

Trying to use the attack to bolster the crumbling credibility of Bush’s “war on terror,” the editorial continued, “There’s been a lot of talk lately that the failure to discover any stockpiles of WMD in Iraq proves that the terror threat isn’t ‘imminent’ and that we can return to our pre-9/11 way of countering it. Is ricin’s arrival in a Senate mailroom imminent enough?”

The Journal’s online editor James Taranto took a swipe at the World Socialist Web Site, claiming that the mailing to Senate Republican leader Frist refuted the argument, made by the WSWS in October 2001, that the anthrax attacks were likely carried out by right-wing extremists who had targeted Democratic Party leaders in the Senate for political reasons.

Only hours later, however, came the White House revelation of the previous ricin mailing, clearly associated with a right-wing extremist opposition to federal regulations. This position is uncomfortably similar to that espoused by the Journal itself, in its incessant tirades against any restriction on the “freedom” of businesses to overwork, maim and even kill their workers.