By Paul Reynolds
World Affairs correspondent, BBC News website
President Bush's defence of a secret programme of wiretaps within the United States shows that the issue of presidential powers in time of war is as alive today as it has been throughout American history.
It was an issue addressed in the constitution and one that saw decisions by Abraham Lincoln and Franklin Delano Roosevelt tested in the courts.
Cicero's comment that "in time of war, the laws are silent" is therefore being constantly challenged.
Under the programme, Mr Bush authorised the National Security Agency (NSA) to listen in to international phone calls and intercept the international e-mails of American citizens and others inside the US without warrants from a special court.
Normally the NSA is allowed to freely intercept only those communications that are wholly outside the US (a task in which it is helped by the British GCHQ at Cheltenham). Anything monitored domestically and likely to involve a US citizen or permanent resident has to be approved by a special court known as the Foreign Intelligence Surveillance Court (FISA).
However, after the attacks of 11 September 2001, Mr Bush decided that FISA was too cumbersome an instrument. It had been set up for the more leisurely monitoring required during the cold war, he argued, and could not cope with the rapid demands of the war on al-Qaeda.
A FISA warrant can approve a wiretap retrospectively but the administration decided that even this would be too slow - and was apparently nervous that some requests might even be turned down.
So the president allowed the NSA to pick up calls and e-mails being made from and to the US. Purely domestic calls still have to be authorised by a FISA warrant.
The programme was revealed by the New York Times recently, a decision Mr Bush called "shameful".
According to the Times, about 500 people are subject to monitoring at any one time and there have been successes.
"Several officials said the eavesdropping programme had helped uncover a plot by Iyman Faris, an Ohio trucker and naturalised citizen who pleaded guilty in 2003 to supporting al-Qaeda by planning to bring down the Brooklyn Bridge with blowtorches. What appeared to be another Qaeda plot, involving fertiliser bomb attacks on British pubs and train stations, was exposed last year in part through the programme, the officials said," the Times reported.
At a news conference at the White House on Monday, Mr Bush offered two defences of his decisions.
"As president and commander-in-chief, I have the constitutional responsibility and the constitutional authority to protect our country. Article II of the constitution gives me that responsibility and the authority necessary to fulfil it. And after September 11th, the United States Congress also granted me additional authority to use military force against al-Qaeda," he stated.
Article II of the constitution says the president will swear an oath of office with these words: "I do solemnly swear (or affirm) that I will faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States." It also appoints the president as Commander in Chief.
Those therefore are the powers Mr Bush says he is exercising.
The additional authority granted to him by Congress, to which he also referred, was a resolution passed on 14 September 2001.
This authorised the president "to use all necessary and appropriate force against those nations, organisations, or persons he determines planned, authorised, committed, or aided the terrorist attacks that occurred on September 11 2001, or harboured such organisations or persons, in order to prevent any future acts of international terrorism against the United States by such nations, organisations or persons."
Issue of oversight
Mr Bush also said that senior members of Congress had been briefed on the programme and that there was therefore congressional oversight of it.
However Democratic Senator John D Rockefeller, vice chairman of the Senate Intelligence Committee, has written to Vice President Dick Cheney complaining that the briefings are inadequate. He said that "given the security restrictions associated with this information, and my inability to consult staff or counsel on my own, I feel unable to fully evaluate, much less endorse these activities."
And the Republican chairman of the Senate Judiciary Committee Arlen Specter has said he will hold hearings on the issue, especially as Judge Samuel Alito, the president's nominee for the Supreme Court, has said that he doubts if the oversight offered is adequate.
However the Acting House Republican Majority leader Roy Blunt said he was "personally comfortable" with what he knew of the programme.
Meanwhile the Washington Post has reported that one of the eleven FISA judges, US District Judge James Robertson, regarded as a liberal, has resigned in protest at the president's move.
Lincoln and Roosevelt
Mr Bush is not the first president to test the limits of his constitutional powers. In 1861 Abraham Lincoln suspended habeas corpus (the requirement that a prisoner be brought to a court for detention to be justified) in Maryland and some other areas of the Union as the capital Washington itself came under threat.
He did so under the article of the constitution which says: "The privilege of the writ of habeas corpus shall not be suspended, unless when in cases of rebellion or invasion the public safety may require it."
Abraham Lincoln suspended habeas corpus
Lincoln's order was declared illegal by Justice Roger Taney sitting in the Maryland federal Circuit Court who said that only Congress could do this, but Lincoln, who regarded Taney as a man of the South, took no notice. However after the Civil War, the US Supreme Court itself limited the effect of a suspension by ruling that this did not automatically allow recourse to military courts.
Internment of Japanese-Americans
In World War II, President Roosevelt issued an executive order to lock up 120,000 Japanese-Americans in internment camps. This was upheld in by the Supreme Court, though with a strongly argued minority dissent, in a case brought by 22-year-old Fred Korematsu, who had refused to report to an assembly point.
The presidential order remained a matter of great controversy and in 1983 Korematsu's conviction was overturned.
In 1988 President Reagan signed into law a Civil Liberties act which included this apology:
"For these fundamental violations of the basic civil liberties and constitutional rights of these individuals of Japanese ancestry, the Congress apologises on behalf of the nation."