Washington, Mar 19: US President George W. Bush will mark five years since the US-led invasion of Iraq Wednesday with a robust defence of his strategy and a warning that withdrawal would hand victory to Al Qaeda.

He will acknowledge the high cost of the war but insist last year’s ‘surge’ of US troops into Iraq ‘opened the door to a major strategic victory in the broader war on terror,’ a gain which must be consolidated, not abandoned.

Both Democratic contenders for the White House have pledged to pull troops out of Iraq, which along with the economy is one of the top campaign issues ahead of November’s presidential elections.

According to pre-released extracts of his speech at the Pentagon Wednesday, Bush will note the ‘understandable’ debate over ‘whether the war was worth fighting ... whether the fight is worth winning ... and whether we can win it.’

‘The answers are clear to me: removing Saddam Hussein from power was the right decision-and this is a fight America can and must win,’ he will say.

Bush will admit to ‘moments of triumph and moments of tragedy’ in Iraq, and acknowledge the war had ‘come at a high cost in lives and treasure,’ but argue this was nothing compared to the cost to the United States if its enemies won.

Last year’s surge was a response to growing violence that ‘would have worsened, spread and could eventually have reached genocidal levels,’ the president will say, adding that the extra troops turned the situation around.

Now, he will argue, ‘Iraq has become the place where Arabs joined with Americans to drive Al Qaeda out’ and the challenge ‘is to consolidate the gains we have made and seal the extremists’ defeat.’ Pulling out too fast would see ‘the terrorists and extremists step in ... fill the vacuum ... establish safe havens... and use them to spread chaos and carnage,’ he will say, adding it could also embolden countries such as Iran.