You can turn ESP off, button on the dash. The description earlier in this thread was for traction control, ESP is different.
http://www.jeep.com/en/4x4/ has a decent description of the Jeep 4WD systems. The liberty has the command trac or the optional selec trac.
The Command-Trac transfer case has four positions: 2-HI, 4-HI, Neutral, and 4-LO. The selector is placed in 2WD HI for regular driving, this allows the two rear tires to receive power. The second position, 4WD HI, is used for driving on slippery or loose pavement. This position locks both the front and rear drive shafts together splitting engine power equally between all four tires. The third position, Neutral, disengages both drive shafts from the transfer case allowing the car to roll freely; this is used for towing behind another vehicle, for example. The last position, 4WD LO is used for situations in which there is very little traction. This position, like 4WD HI locks both the front and rear drive shafts together, and by using a lower gear ratio, allows for 2.72 times more torque (however, the speed is limited to around 25 MPH max). It should be noted that using 4WD HI or LO on dry pavement is hazardous to vehicle components, through drive line binding and wheel-hop.
The Selec-Trac transfer case is an automatic case where the transfer case has a clutch pack that, when fully engaged, locks the case as above. When not engaged, it acts like the 2WD mode above. The amount of clutch pack engagement is controlled by the jeep's computer which senses things like wheel slip.
The selector controls the case only, no lockers in the diffs as you would get with some of the QD systems.
Liberty's all-speed traction control system uses sensors to monitor wheel spin, reducing engine speed, applying the brakes to spinning wheels, and transferring torque to the appropriate wheel when slippage is detected. I don't think you can turn it off.
During extreme steering maneuvers ESP helps maintain control by sensing when the vehicle is starting to over- or understeer. ESP automatically applies individual brakes or controls the throttle to help you stay safely on course. When you don’t want the extra hand, ESP is specially tuned for performance handling so you can switch it off.