Larison piles dirt atop the coffin of the "special relationship":
Had Britain under Blair not become a lockstep supporter of Washington’s line on anti-terrorism, nonproliferation and regime change, and if Washington had therefore not had the fig leaf of British support and the political capital that came from Blair’s endorsement of the invasion, it is remotely possible that the invasion might never have taken place.
Regardless, it would have been entirely appropriate for Britain to have refused to participate in the war, as Britain’s role and its interests in the region are not identical to the U.S. role and interests as Washington understands them. What’s more, had Britain assumed the role of a critic and opponent of the invasion, that could have lent considerable weight to the antiwar case.
Britain would have been doing America a far greater favor by working to prevent our government from making a terrible blunder in 2003.