Chilcot: Five Key Questions About the Iraq War Inquiry

In all the sound and fury of Brexit, an approaching milestone in British politics has until this week been largely ignored. But fanfare or not, Wednesday will see the publication of the final report of the Chilcot Inquiry into the U.K.'s involvement in the Iraq war between 2001 and 2009.

The day could mark a seismic moment for the reputations of senior intelligence figures, military chiefs and politicians in the last Labour government. Most of all, attention will focus on former Prime Minister Tony Blair, whose ongoing career in public life has been haunted by the war and the alleged mis-steps he made in planning and conducting it.

But any inquiry, even one as broad and as long in the writing as this one, has its limitations. Here's five key questions about what the report, led by former civil servant John Chilcot, will and won't say.

Will it say whether the war was illegal?

Iraq exercises the British public, particularly those on the left, like few other issues, and legalistic rhetoric has always been common in criticism of it, including a tendency to brand those involved in planning it as "war criminals."

But Robin Butler, the peer who conducted an earlier inquiry into the intelligence involved in planning the war, said Monday on the BBC's Today programme that the legality of the war "wasn't actually put to" Chilcot and was unlikely to form part of the report. "The inquiry is not a court of law. The members of the committee are not judges, and nobody is on trial," the inquiry's website says.

Will Tony Blair be "impeached?"

At the weekend, The Guardian reported that a group of MPs led by former SNP leader Alex Salmond are set to trigger an ancient law to try and ban Blair from ever holding public office. The law requires an MP to propose a motion on impeachment and then provide a document as evidence, which in this case could be the inquiry. Blair would then be brought before parliament and a simple majority would be required to convict him.

While this is possible in theory, the document is unlikely to level criminal charges against Blair, and a majority of MPs in favor of convicting a former prime minister in this way would be difficult to obtain.

Who is likely to be in the firing line?

One of the reasons for the report's long delay (the inquiry was set up in 2009) is that many of those mentioned in it were given a right to reply, in a process known as "Maxwellisation." The Sunday Times reported in May that many could be in for an "absolutely brutal" savaging, in the words of one source. Former Home Secretary Jack Straw, ex-Mi6 head Richard Dearlove and Blair himself are among those who reportedly could be heavily criticized.

Will the report apportion blame for what has happened to Iraq since the war?

Iraq is now at crisis point, with much of the country still overrun by fighters from the Islamic State militant group (ISIS), trust in government low, and Shia militias of uncertain loyalty spread throughout the nation. The report's remit ends in 2009, and so it won't pass a direct judgment on how much blame for this situation lies with Western powers. But it is widely expected to criticize military and political leaders for the lack of a proper plan to deal with the aftermath of a bruising invasion and the insurgencies that followed it, as well as for governing the country and ensuring a smooth political transition.

Will we find out more about Blair and George Bush's relationship?

Yes. While it's hard to predict the full scope of what the report will say on U.S.-U.K. relations, we do know that alongside it 29 of Blair's private memos to Bush will be published, with some redactions. This is unlikely to include much information on Bush's views in deference to U.S. sensitivities, but it may shed light on how Blair approached discussions of the run-up to the war with his counterpart across the Atlantic.