George Tells Sam That A Bribe To A Certain Corrupt Los Angeles County Official W

George tells Sam that a bribe to a certain corrupt Los Angeles County official would buy a contract for the sale

of prescription drug services to a large county hospital. Sam recruits Tom and Steve, who own Sav-Rx, which provides prescription drug benefits from various manufacturers. Tom is asked to pay a “finder’s fee” to George. After several attempts via phone and email – Tom does not pay. Finally, Steve writes a Sav-Rx check to George for $6,500- saying it was to help Sam. George is an FBI agent- the county official and the deal are all fictional. Steve is arrested and charged with conspiracy to commit bribery. At trial, the government admits that Steve was not pre-disposed to commit the crime. 

What defense, if any, can Steve use in his case and why?