Is a US attack on Syria now inevitable?

US warships are in the Middle East, but no orders for deployment have been given

The tone of the White House changed over the weekend.

It is now much harsher towards the Syrian government - more certain that the deaths last week were caused by a chemical weapons attack and that it was carried out by President Bashar al-Assad's government.

A statement derided the idea of the inspectors being allowed in now, suggesting shelling had already destroyed the evidence.

Doubtless, there will be similarly pointed words about the shooting at the inspectors as they attempted to begin an investigation.

US President Barack Obama was given a range of military options and spoke to the leaders of his key military allies, Britain and France.

Three US warships are in the region and another is heading there. Many in Congress are calling for them to carry out a limited cruise missile strike.

It all seems to point in one direction.

Repeating Iraq mistakes?

The British newspapers are suggesting there will be a strike this week.

I cannot help remembering a brilliant, defunct comedy series The Day Today, which showed a TV studio being transformed into a "war desk" with alarms screaming, red lights flashing, machinery rapidly swinging into place and lights dimming dramatically.

It captured exactly the way some in my business get over-excited by the possibility of conflict.

I have been stressing President Obama's caution and reluctance to take action. But now it does seems difficult for him to back down without losing face. Unless something changes.

One thing has long puzzled me.

While a government using chemical weapons against its own people is an affront that may demand international action, it seems obvious that a far greater horror from the US point of view is those weapons being used against its own people or allies.

The great fear since the 9/11 attacks has been such weapons falling into the hands of those the West regards as terrorists.

Given that one of the main opposition groups in Syria has formally declared allegiance to al-Qaeda, that must be a real possibility.

It would seem to me to be a core US interest to secure those weapons and put them beyond use. But I have seen very little discussion of such an option.

Remember, too, that American and Russian diplomats are heading for the Netherlands to plan peace talks. What might not enhance their chances of success is a US attack. But threats might.

While President Obama may not take much notice of Russian warnings, their central sentiment may strike a chord - the Russians say if the US goes to war it will be repeating the mistakes of former President George W Bush in Iraq.

That danger surely looms large in President Obama's mind.

The American military has consistently warned Syria is a hard nut to crack. It is not Libya, and its sophisticated air defences would take a lot of effort and commitment to overcome.

It would be surprising if President Obama took action without trying to obtain the maximum possible international backing, and that probably means giving the UN route more time.

I may be wrong: the red lights could soon be flashing and the war desk swinging into action. But while the rattling may be loud, the sabre has not yet been drawn.

'Chemical attack': What we know

• 01:15: 21 August (10:15 GMT 20 Aug): Facebook pages of Syrian opposition report heavy fighting in rebel-held districts of Ghouta, the agricultural belt in eastern Damascus

• 02:45: Opposition posts Facebook report of "chemical shelling" in Ein Tarma area of Ghouta

• 02:47: Second opposition report says chemical weapons used in Zamalka area of Ghouta

• Unverified video footage shows people being treated on pavements in the dark and in a makeshift hospital

• Reports say chemical weapons were used in Ghouta towns of Irbin, Jobar, Zamalka and Ein Tarma as well as in Muadhamiya to the west, but this is not confirmed

• Syrian government acknowledges military offensive in the Ghouta area but denies chemical weapons use