Washington: The theatrics in war are vital, especially in the early days.

So when US fighter jets on Monday launched their 162nd mission since taking to the skies of northern Iraq early in August, they did something completely different - they flew deep into Iraq to attack an Islamic State position south-west of the capital, Baghdad.

Interesting.

US Central Command would have us believe that they were simply responding to a call from their Iraqi allies, as opposed to their Iraqi enemies, to help out Iraqi government forces who were in a patch of bother.

But there was more to it than that. In agreeing to the Iraqi request, the US military was significantly expanding its area of operation, for the first time since President Obama's announcement last week that the war on the Islamic State group (also known as ISIL) was to be ramped up.

The rumble of American hardware in the skies over the capital, for the first time since the US withdrew from Iraq at the end of 2011, would have been cause for pause by ordinary Iraqis. It revealed that ISIL fighters were so well dug in near the capital that the only way for national security forces to dislodge them was to appeal for American air power.

A statement issued by Central Command late on Monday explained that the strike, which was said to have destroyed six ISIL vehicles and one of the movement's fighting positions, was the first "taken as part of our expanded efforts beyond protecting our own people and humanitarian missions".

But the theatrics of this bold move would be reviewed way beyond Baghdad - in Paris and Washington in particular.

It confirmed for the US Congress that Obama is pressing ahead in the belief that he has all the authority he needs for this war, even as Californian Republican Buck McKeon, who chairs the House of Representatives Armed Services Committee, sought to amend a funding measure for the war seeking to ensure that the Pentagon arms and trains "appropriately vetted" Syrian rebels.

On Tuesday another Californian congressman was expected to introduce an authorisation measure for the use of "all necessary and appropriate force" in the war on ISIL and the defence chiefs were to appear before the Senate Armed Services Committee to be quizzed for the first time on a conflict which the attack near Baghdad confirmed was under way, with or without their formal approval.

Similarly, the strike would have confirmed the start of the expanded conflict, even ahead of finalising the membership and mandate of the global coalition that Obama is assembling, as representatives of 26 countries met US Secretary of State John Kerry in Paris.

Without going into specifics, they pledged support for the new government in Baghdad, including "appropriate military assistance ... in accordance with international law and without jeopardising civilian security".

In the same way that Obama has framed this conflict in terms of what it is not, which is that it is not to be seen as or compared with the last US-led military venture in Iraq and the Afghanistan war, the assembly in Paris was more about who was not there - to wit, Iran.

Kerry appeared to be hinting at a need or desire for dialogue with Iran on the conflict when he said that the US was open to talks with Iran, but he had opposed their attendance in Paris, probably in deference to the Saudis and the United Arab Emirates, which announced that they were present only because the Iranians were absent.

And while all of that was going on, no one seemed to notice or to mind that the air strike near Baghdad, effectively the first shot of Obama's new and expanded war, had been fired by an American aircraft. Pity that - because it would have packed a more powerful punch had it been conducted by one of the Arab air forces.