(CNN) -- Ever since the 2003 invasion of Iraq exposed deep-rooted religious and ethnic divisions, analysts have suggested giving up on the colonial-era borders of modern Iraq and dividing the country. Jihadists have felt the opposite, that the region should be united into a new caliphate -- indeed that is precisely what the militant group the Islamic State in Iraq and the Levant (ISIS) declared this week. Both are wrong. The lines drawn by the British and French colonial powers in 1916 became, after the collapse of the Ottoman Empire, the borders of new Arab states. Over the years, these lines splitting the Levant into Syria, Lebanon, Jordan and Iraq have been enormously contentious, to the extent that it is often argued the region might be better without them. Either removing these lines altogether and returning to the world of the early 20th century, or drawing them smaller and tighter still.
@highlight
Iraq's borders were mapped out by the British and French colonial powers during WWI
@highlight
Faisal Al Yafai writes that the borders -- though contentious and flawed -- have broadly held
@highlight
Plans for an Arab caliphate or dividing Iraq into statelets are not realistic, he says
@highlight
Seeking to change them now is a recipe for a generation of war, Al Yafai writes
Any division of @placeholder has to take into account people, politics and economics.
An estimated one million Iraqis are already on the move within @placeholder, internally displaced from their homes.