(CNN) -- David Cameron must have whiplash. Practically overnight this week, the British prime minister went from being one of the leading voices demanding that Syria's President Bashar al-Assad be punished for using chemical weapons, to a humbled, chastened politician with his hands tied. 

British lawmakers voted Thursday night against even the possibility of using force against Syria, forcing Cameron to concede bluntly, "We will not be taking part in military action." 

What do Syria's neighbors think? 

The vote was close -- seven MPs out of the 557 who voted could have changed the result -- and the outcome was a shock. Prime ministers aren't supposed to lose votes on the use of military force. British media said it hadn't happened in hundreds of years. 

But although the result was stunning in one sense, in another it wasn't surprising. 

Over more than seven hours of debate on Syria loomed one chilling specter: Iraq. 

Bergen: Syria is a problem from hell for the U.S. 

Britain feels badly burned by the way Tony Blair led the country into war there a decade ago, and Cameron was fighting a defensive battle against the memory of Blair from the moment he kicked off debate in the House of Commons: "I'm deeply mindful of the lessons of previous conflicts, in particular the deep concerns of the country of what went wrong in Iraq. We're not invading a country; we're not searching for chemical weapons." 

It's an argument he needed to make. 

Why Russia, China, and Iran are standing by Syria 
Who must have whiplash?
Who is he
Are his hands tied?
Was he demanding Bashar al-Assad be punished
Who is that
Who voted against the use of force
When?
against who?
Was the vote close
How many MPs voted
What was the thing looming over the debate
What was the specter?
How many hours was that debate?
How does Britain feel
What did he do?
Who was fighting a defensive battle?
WHO was fighting a defensive battle?
David Cameron
David Cameron 
British prime minister
British prime minister 
yes
ian w
yes
unish
British prime minister
British prime minister
British lawmakers
British lawmakers 
Thursday night
 Thursday night 
using force against Syria
using force against Syria
yes
was close -
557
557 
Prime ministers aren't supposed to lose votes on the use of military force
Prime ministers aren't supposed to lose votes on the use of military force
Iraq.
Iraq. 
Over more than seven hours
Over more than seven hours
badly burned by the way Tony Blair
badly burned by the way Tony Blair
led the country into war there a decade ago
led the country into war there a decade ago
against the memory of Blair
 against the memory of Blair 
Cameron
Cameron