In federal criminal cases, the government has the burden of proving the defendant's guilt beyond a reasonable doubt. The ease with which this can be done depends on numerous factors, from the evidence that is available (and legally admissible in court) to the defendant's choice of legal representation. Federal prosecutors must have sufficient evidence to prove each element of the offense, and they must be able to successfully overcome defense counsel's arguments as to why a jury verdict of 'guilty' is unwarranted.