CA Reneges on Guard at Border:  After agreeing last week to dispatch National Guard troops at the California/Mexico border, the State has withdrawn the offer announcing that it will not allow its troops to fix and repair vehicles, operate remotely-controlled surveillance cameras to report suspicious activity to the Border Patrol, operate radios and provide "mission support," which can include clerical work, buying gas and handling payroll.   Elliott Spagat of the Associated Press reports that according to state officials these activities are too closely tied to immigration enforcement to be performed by the troops.  Negotiations between state and federal officials soured Friday and over the weekend after state authorities told federal officials that they would not participate in vehicle maintenance and the other jobs outlined for an initial phase across the border in California, Arizona, New Mexico, and Texas, the U.S. officials said.