By Paul Reynolds BBC News Online World Affairs correspondent

The vote by Congress to authorise President George W Bush to use force against Iraq demonstrates the power of patriotism and the power of the presidency in the United States.

Patriotism has become a major factor in American society since 11 September 2001.

Saddam Hussein's defiance, if not ended, is a threat to every nation that claims membership in the civilised world

Senator John McCain

The decision hugely strengthens the hand of President Bush - the Commander-in-chief - both for diplomacy and for possible war.

The speed with which the Senate rallied to the resolution passed first by the House of Representatives showed how anti-war sentiment has been overwhelmed in a rush to support the President. It had been thought that the Senate would take a little more time and be a little more cautious in the powers it approved.

Democrats as well as Republicans flocked to the colours, influenced partly perhaps by the prospect that doubters might be damaged in the forthcoming midterm elections on 5 November and in the presidential election in 2004.

'With one voice'

The two Democrat leaders, Senator Tom Daschle and Congressman Richard Gephardt - both spoken of as possible presidential candidates - voted in favour of the war powers.

The mild-mannered Mr Daschle was reluctant but Mr Gephardt was keen and helped frame the resolution himself.

George Bush did even better than his father did in when he got Congressional approval for war against Iraq in 1991

Mr Daschle commented: "I believe it is important for America to speak with one voice."

Mr Gephardt said that diplomacy should be given "the best possible opportunity" but that "further steps" would be taken "if necessary to protect our nation".

Sentiment on the Republican side was forcefully summed up by Mr Bush's former presidential rival, Senator John McCain, a Vietnam veteran. Saddam Hussein's defiance, he said "if not ended, is a threat to every nation that claims membership in the civilised world".

In essence, the president has the right to determine himself what to do and when

Doubts expressed by the CIA Director George Tenet about the immediacy of a threat from Iraq were swept aside.

General Anthony Zinni, the former head of Central Command - which would be in charge of an attack on Iraq - echoed these doubts.

"I'm not convinced we need to do this now," he said.

George Bush did even better than his father did in when he got Congressional approval for war against Iraq in 1991.

Forty-eight hours

The heart of resolution itself, stripped of no less than 23 preliminary clauses starting with "Whereas", gives Mr Bush the power to "defend the national security of the United States against the continuing threat posed by Iraq" and to "enforce all relevant Security Council resolutions regarding Iraq".

Bush now has the right to decide what to do and when

He has to tell Congress within 48 hours of taking military action why diplomacy had failed and to report back every 60 days.

But in essence, the president has the right to determine himself what to do and when.

He has chosen to go through the Security Council for now, but has his political back covered if that route to Iraqi disarmament is blocked and he turns to war.

The US and Britain have still not, however, got agreement among the five permanent members of the council as to the way forward.

Russia reluctant

Russia is being wooed by the British Prime Minister Tony Blair on a visit to President Vladimir Putin. There is talk of Russia being given assurances that it would not lose out financially if there is "regime change" in Iraq.

But Russia is reluctant to authorise force too quickly and wants to give inspections a chance.

So does France.

Those diplomatic issues remain to be resolved.

Mr Bush has meanwhile won a great political victory.