The United States, United Kingdom and Spain decided on Monday to withdraw their draft resolution seeking the United Nations Security Council's authorisation for war on Iraq.
President George W Bush will talk to the American nation from his Oval office at 2000 EST [1830 IST].
The three allies decided to withdraw the resolution without discussing it in the council after France and Russia repeated their warnings that they would veto it, come what may.
But war clouds in the Gulf only grew darker, as the US earlier on Monday asked UN and International Atomic Energy Agency inspectors to leave Iraq at the earliest.
The three allies may now go to war on the basis of UN Security Council Resolution 1441.
British Ambassador to the UN Jeremy Greenstock said, "The co-sponsors reserve the right to take their own steps to secure the disarmament of Iraq."
The ambassador said the allies could not agree to the alternative plan suggested by "one country" [read France] to secure Iraq's compliance with Resolution 1441.
US Secretary of State Colin Powell said later that while Iraq had started making slow, grudging progress in meeting the requirements of Resolution 1441, it was nowhere near what the US was looking for.
He said the president in his address to the nation would make it clear that this situation could not continue and issue an ultimatum to President Saddam Hussein to leave Iraq.
Powell said American and British legal experts had said that the use of force could be justified under Resolution 1441 and a second resolution would not be required.
He said this was the position of the US even at the time Resolution 1441 was passed by the Security Council.
He said the new resolution that was dropped at the last minute on Monday was not because the earlier one did not authorize the use of force, but to help some of America's allies (Britain and Western Europe) to show their people, who are opposing the war, that one last-ditch attempt had been made to avert fighting.
He said each and every member who voted for Resolution 1441 on November 8, 2002, knew that serious consequences would flow from failure to comply with it, and that serious consequences could even entail war.
He said the US would not be happy with the departure of just Saddam Hussein, but of all members of his family and inner circle in positions of power in Iraq.