In some cases it is an offense by itself to plan or attempt to commit a
crime; this in called an
inchoate offense. Examples of inchoate offenses include
conspiracy to commit
murder and
attempted burglary. There can be various causes of failing in the attempt, for example
arrest prior to committing the crime.
See also:
http://faculty.ncwc.edu/toconnor/293/293lect05.htm