In his extraordinary first week in the Oval Office, President Barack Obama signalled his intention to return America to its place of moral leadership in the world and then proceeded to do something about it.
By his second day in office, Mr Obama had driven a stake through George Bush's "War on Terror" and as the week went on and the millions who came to Washington for the inauguration returned home on an emotional high, Mr Obama signalled that the country was under new management.
He opened the White House to strangers for a few hours, visited the cubbyholes where the press corps works and revealed that he would be hanging on to his BlackBerry.
One of his first official acts was to freeze the salaries of his senior staff, a nod to the pain being felt by millions of unemployed Americans.
And he implemented the toughest ethics rules ever in the White House. The door through which relatively poorly paid staffers went on to become highly paid lobbyists – after a brief cooling-off period – was slammed shut.
By Thursday, Mr Obama had plunged into the quagmire of peacemaking in the Middle East and appointed his own envoy to the region, George Mitchell, who negotiated the Good Friday agreement in Belfast.
Yesterday, Mr Obama grappled with the financial meltdown and his plans to revive the economy with a cash infusion of up to a trillion dollars. Along with a daily security briefing, Mr Obama revealed that he now also receives a daily economic briefing, so deep is the unfolding crisis.
He also visited the State Department, which became a shadow of its former self under Mr Bush as resources were diverted to military struggles. With Hillary Clinton at his side, Mr Obama spoke of putting diplomacy and development at the heart of his foreign policy.
An early gesture will be restoring abortion funding to family-planning groups around the world. Under a rule that Ronald Reagan instituted, no US money could be used to help an organisation that had links to abortion; even groups helping prostitutes avoid Aids were banned from receiving funds. All presidents enjoy a honeymoon period and Mr Obama is fortunate that his approval ratings are so high – the signs are that he intends to use his first 100 days in office to get major reforms under way before he has expended too much political capital.
Restoring America's moral stature, by returning to an era of respect for international institutions and laws, was at the heart of his early initiatives. In his inaugural address, Mr Obama carefully said, "our nation is at war, against a far-reaching network of violence and hatred" – he used the word "war" only to describe specific events.
US diplomats acknowledge that Mr Bush's policies became al-Qa'ida's most effective recruiting sergeant. Some of the most controversial tools in Mr Bush's armoury included the humiliation, mistreatment and torture of terror suspects, which were used as a rallying cry for anti-Americanism.
Foreign fighters captured in Iraq cited the depravity of Abu Ghraib prison and the images of shackled and hooded inmates at Guantanamo as the reason they followed Osama bin Laden's call to arms against America. Many of those arrested after bomb plots in Britain and Europe also cited the images of detainees being herded behind the wire at Guantanamo as justification for their actions.
With the stroke of a pen, Mr Obama halted his predecessor's deeply controversial policy of using executive orders to skirt around the US constitution and international legal obligations under the Geneva Conventions.
As the architecture of the Bush anti-terrorist crusade was dismantled, there was barely a whisper of protest from the US military establishment which benefited from the resources lavished on the war on terror. After eight hard years and two hot wars, the generals and spymasters were not mourning a policy that had brought more grief than honour to its military.
There were, however, murmured complaints from the CIA that a total ban on torture was unwise. Mr Obama seems to have created a loophole in the form of a committee to study whether the permitted interrogation techniques are too limiting "when employed by departments or agencies outside the military" – in other words, by CIA agents. A "special task force" may yet provide America's intelligence agencies with "additional or different guidance" on how much force interrogators can use on terror suspects.
Mr Obama made clear that counter-terrorism operations would continue and may even be stepped up. Yesterday, US drones fired missiles against targets inside Pakistan, killing 14 people, in the first such attack since his inauguration. But the prison at Guantanamo Bay is to be closed within a year. His administration is now grappling with how to deal with a handful of dangerous terrorists and a majority of detainees who were never serious players. Adding to the complications, a former Guantanamo Bay detainee has allegedly emerged as a deputy leader of al-Qai'da's organisation in Yemen and has taken part in a deadly attack on the US embassy there.
Action man: A day-by-day guide to an extraordinary week
*Tuesday
One of the new President's first acts was to suspend the Guantanamo Bay military tribunals for 120 days.
*Wednesday
Circulates plan to shut Guantanamo in a year. Orders pay freeze for senior White House staff. Orders restrictions on lobbyists. Opens government agencies to public scrutiny. Chairs economic and security briefings. Hosts "open house"at White House with Michelle Obama. Telephones Middle East leaders.
*Thursday
Orders the closure of Guantanamo in a year and a prisoner review. Also closes secret CIA prison network. Bans torture and rendition.
Names the Middle East and Aghanistan/Pakistan envoys at event also attended by the Secretary of State, Hillary Clinton. Tours the White House press room.
*Friday
Lifts abortion funding restrictions. Meets Congress leaders oneconomic rescue package. Telephones Gordon Brown.
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