Ex-Cabinet minister Clare Short has launched a bid to give MPs the final say over whether troops go to war.
Clare Short wants Parliament to have a veto on war
Ms Short said Tony Blair - or any future prime minister - should be forced to seek Parliament's consent for military action.
But Commons Leader Geoff Hoon kept speaking long enough to prevent a vote being taken on the bill.
It will now go back into the queue of private members' bills and will not be debated again until next year.
The Commons chamber was unusually crowded for a Friday for the second reading debate on Ms Short's plans.
The former international development secretary denied her proposal was an attempt to re-run the arguments about the run-up to the Iraq war.
But she also launched a stinging attack on the "informality" of Tony Blair's decision making ahead of the invasion.
She told MPs: "Decisions are not well made when they are made informally."
And "you can not leave it to the personality of individual prime ministers" to decide such important constitutional issues.
She said it was Parliament's "duty" to act as a restraining influence against the tendency of power to concentrate in Number 10.
Ms Short told MPs: "The accountability of the executive to Parliament is a very important democratic principle which should surely be extended to the making of war.
"But having recently lived through the way in which the decision to go to war in Iraq was made, I strongly think that we owe it to our armed forces and the reputation of our country to put in place arrangements which will ensure that the decision to go to war is more thoroughly considered."
Under the terms of Ms Short's private member's bill, both Houses would have to be shown the case for war and its legal justification before voting on whether to give the go ahead.
A prime minister would still be allowed to take urgent action without approval but would be forced to pull the troops back out if Parliament then rejected the move.
She said her move had the backing of a large number of MPs from all parties as well as the families of soldiers killed in the conflict.
Tony Blair allowed a vote two days before the start of the Iraq war but could have sent troops into action using the "royal prerogative".
During the general election campaign, Chancellor Gordon Brown suggested the Iraq war vote had set a precedent so people would expect votes on military action in future except in the most exceptional circumstances.
But Mr Blair said the chancellor was simply backing the current position rather than calling for constitutional changes.
In Friday's debate, Mr Hoon told MPs Ms Short's bill could have "unforeseen and undesirable" consequences.
The government always kept Parliament informed about military action - and had allowed the Iraq vote.
"Today we're not talking about unnecessary powers or powers possessed by some historic accident," he said.
"We're talking about a key power possessed by the executive as a matter of pragmatic necessity if it is to be properly effective."
Governments needed freedom of manoeuvre on foreign affairs and defence, he argued.
Liberal Democrat MP Martin Horwood said it was "disgraceful" Mr Hoon had kept talking and so prevented the bill moving forward.
But Mr Hoon said he had listened to many speeches in the debate and needed time to answer the points raised.