The debt ceiling is an artificial constraint to federal spending imposed by Congress.  Exceeding it will have no negative consequences on the economy.  As the sovereign issuer of the US dollar, the federal government can create and spend as much money as it wants to and give it to someone, per former Fed Chair Alan Greenspan.  

Furthermore, unlike a currency user such as a private household or business, a state or local government or a nation like Greece, the US government can never go broke involuntarily.  It also doesn't need to tax or borrow in order to fund spending.  

The only natural constraint to federal spending is inflation which is a result of too much money (demand) chasing too few resources.  Such resources include oil, food, cars, houses, land or people, and is where real inherent value lies. Our federal taxes help keep inflation under control by removing excess dollars from the economy, thus giving it value.

A resource limit would be better than a debt limit IMO.