London(CNN) Former British Prime Minister Tony Blair says going to war in Iraq "was the hardest, most momentous and agonizing decision" he took during his decade in power.
Newly declassified letters Blair sent to President George W. Bush reveal his soul-searching in the lead-up to war, during the 2003 invasion and as Iraq descended into chaos.
The correspondence, released as part of the Chilcot report into Britain's role in the Iraq War, is one-sided --Bush's letters were not made public. But it offers a frighteningly prescient glimpse into the sectarian rifts that continue to divide the troubled country more than a decade after Bush declared, "Mission Accomplished." Here are some of those letters:
Blair acknowledges global reluctance for military action in Iraq but says "for sure, people want to be rid of Saddam." He suggests a road map for regime change, including pressuring Syria, stoking rebellion inside Iraq and getting Russia on board.
Blair pledges support for Bush's plan to remove Saddam Hussein but warns other European allies will not be on board without U.N. authorization. He suggests they pull together evidence of weapons of mass destruction and link the Iraqi dictator to al Qaeda -- and suggests that military action could get underway as early as January 2002.
Bush set out his view of the "grave and gathering danger" posed by Hussein and urged the United Nations to get tough on Iraq in a speech to the U.N. General Assembly. Blair called it "a brilliant speech" in a letter to Bush on the same day.
As the march to war ramps up, Blair sends a checklist to Bush that includes a timetable for weapons inspections and questions around military and diplomatic options. He asks if there is a sound plan on "avoiding civilian casualties" in pen on the typed letter.
In a wide-ranging letter six days after the war begins, Blair justifies the invasion despite the lack of weapons of mass destruction: "(T)hough Iraq's WMD is the immediate justification for action, ridding Iraq of Saddam is the real prize. ... The problem is that a ludicrous and distorted view of the U.S. is clouding the enormous attraction of the fundamental goal."
Six months after the invasion, Blair acknowledges that things aren't going as well as hoped. He says security must be shored up and asks if Paul Bremer, the head of the U.S.-led coalition's occupation government in Baghdad, needs more help.
Blair says things are tough on the ground and laments the failure to find more evidence of weapons of mass destruction. "But this was always about more than that," he writes. "It was about a global threat. The starting place was Iraq because of the history."
As sectarian tensions begin to build, Blair asserts the majority of Iraqis are on board with the coalition's plan for Iraq -- but that "a minority of extremists and terrorists want to take them back to the ways they are all too familiar with." He says Shia cleric Muqtada al-Sadr must be handed over to authorities and must disband his militia.
Blair writes to Bush about the Iraqi media and his ideas around making the Prime Minister's media operation "tip-top." In a note to the U.S. President, he says they should be commissioning constant polling on Iraqis.
Blair outlines the current state of the debate over the war, saying the truth was "somewhere in between" the pro-war people, who maintained weapons of mass destruction existed, and the anti-war movement who said it was a fraud. "What we have to do is avoid the absurd notion that therefore there was no threat at all," he says.
Returning from a Christmas visit to British troops stationed in Iraq, Blair writes to Bush to tell him that, though people are "more upbeat than I expected," there is still suspicion of the coalition forces' motives for being in Iraq.
Three years after the war began, Iraq is riven by sectarian violence and political instability, threatening to tip the country into civil war. Blair writes to Bush bemoaning the lack of good news.
Following a trip to Iraq to meet the new national unity government, Blair writes a hopeful note to Bush outlining his plans for the country's future and highlighting the need to involve the Iraqi people.
Shortly after a pre-Christmas visit to British soldiers based in Basra, Iraq, Blair discusses the idea of sending extra troops to Baghdad, and says his forces are "convinced that ordinary Iraqis don't buy into the extremism" damaging the country.