The American congress convenes today to begin debating one of the greatest moral quandaries ever to have exercised the honorable members on Capitol Hill.

Chips down, stakes high: this will be an awesome week for Democracy in America.

President Barack Obama will make his case for a punitive attack on Syria in interviews on all the big networks tonight. His mission is to persuade the American people – and their elected representatives in Washington DC – that the United States cannot “stand by and do nothing” as children are gassed in Damascus.

But he is still a very long way from convincing an exhausted, war-weary, recession-bruised, sceptical – and increasingly isolationist America – that he’s right.

In fact, on the face of it, Barack Obama faces an almost impossible task. A very ‘heavy lift,’ as they say here.

If he loses the congressional vote, he will be left politically dead in the water.

If he wins, there is real fear here that America’s Nobel Peace Prize-laureate president could trigger World War III.

And if that sounds like hyperbole, all I’m doing is reporting what I’ve heard many ordinary Americans saying over the past few days, to me directly, to their congressmen and on TV.

Definitive moment

Historians will look back at these votes in congress as marking a definitive moment for America as a global power; America as the world’s policeman.

Bashar al-Assad – who will also be on US television tonight, denying involvement in the chemical attack – has thrown down the gauntlet, challenging the US president’s authority and testing both Obama’s and America’s resolve.

Some still wonder what possessed Obama to ask Congress to authorise his use of force – particularly as he believes that as president, he has the authority to order a strike without congressional backing.

Perhaps it was a clever ploy, using congress as a political foil, so that if it approved a punitive attack, they could share the blame should regional conflagration result.

Perhaps he figured that what Americans call “the math” was not in his favour and that a ‘No’ vote would allow him, as a very reluctant warrior, to walk away from intervening in the Mid-East for the third time in a decade.

By passing the buck to the lawmakers, President Barack Obama has exposed deep rifts not between, but within the two parties.

‘Enormous pressure’

There are scores of Obama-loyalist Democrat congressmen who now find themselves impossibly torn; their electorate demanding they vote ‘No’.

Even though Obama is likely to win approval from the senate – albeit with just 60 or so of the 100 Senators supporting him – the real battle is going to take place in the House of Representatives. It is a much larger body and, elected every two years, its members are more beholden to their constituents.

There is a Republican majority in the lower house. Some of them will vote with the president but there are many in Obama’s own party who oppose him on this issue. The current tally shows the ‘No’s’ or those leaning ‘No’ are in a clear majority.

In Washington, those poring over congressional whipcounts are predicting that President Obama is going to lose – “and lose big.”

Kansas City Congressman Emanuel Cleaver II, a Democrat, told me: “My constituents believe I will listen to them and there is enormous pressure on me to vote with what I think is about 90 per cent of the people here.” For two hours he had been subjected to a verbal lashing by his constituents in a ‘town hall’ meeting. The vast majority demanded he vote ‘No’.

Mr Cleaver, a former mayor of the Missouri capital and now in his fifth term as its member for Congress, is a friend of Obama and as an African-American and a Democrat, clearly has a profound respect for all the president stands for.

Except on this issue.

“It could hurt the president a lot and I just don’t want that to happen,” he told me. “He has a lot of selling to do. People are saying to me ‘I voted for him twice. I love him! But he’s wrong. Don’t vote with him.’”

At shortly after 10 o’clock this morning, Congressman Emanuel Cleaver II will touch down in DC after the three-hour flight from Kansas City. He will take a 20-minute cab-ride from Reagan National Airport to Capitol Hill.

There, he will receive a classified briefing on the latest US intelligence which reportedly incontrovertibly affirms Bashar al-Assad’s responsibility for what happened in those Damascus suburbs on the night of 21 August. Could that swing it for Barack Obama?

“If I had to vote at this very moment, my vote would be no,” Mr Cleaver told me. “But it would be an injustice to my constituents, and frankly to the administration, to say that my mind is made up and there’s nothing that can be said or done to change it.

“I am looking for critical information from the administration. When you are talking about going to war against another sovereign state, it is no small matter,” he said.

TV slot

Barack Obama will be giving pre-recorded interviews today to six networks: ABC, CBS, NBS, PBS, CNN and Fox News. They will broadcast them at a pre-agreed time this evening.

The president will not address the nation from the White House until Tuesday night.

The thinking behind the timing of this address is in itself a metaphor for the growing isolationism of this superpower.

It’s the first week of the American football season. Ordinarily the president would have made his appeal to much fanfare in a grand Sunday night address. But he couldn’t. The New England Patriots were playing the Buffalo Bills, and the New York Giants were up against the Dallas Cowboys.

America wasn’t much interested in anything else.

And tonight, at 7.10pm Eastern, the Washington Redskins are playing the Philadelphia Eagles. Not a hope of America tuning in to Oval Office TV.

So Barack Obama is to squeeze his presidential request for a BGM-109 Tomahawk Cruise Missile blitz on Syria onto the Tuesday night schedule when the big showdowns won’t get in the way.