if you can legally own a gun, you have nothing to fear from a background check except the fee to conduct the transfer
Criminal background checks violate the presumption of innocence (which was once the cornerstone of the U.S. justice system.
And such checks violate the privacy of the citizen.
And such checks violate our Constitutional Right against unwarranted search and seizure.
Besides, there have been so many laws written over this nation's history that practically every citizen is a criminal (often unknowingly)....
Have you ever exceeded the speed limit?
Have you ever jay walked?
Have you ever cursed in public or spit on the sidewalk (illegal in many places)?
Have you ever parked illegally?
Have you ever taken some medicine prescribed to someone else, like you had a migraine headache and a buddy gave you one of his prescribed migraine tablets?
Have you ever taken mail from your neighbor's mailbox while they were on vacation?
Have you ever connected to a wifi spot without permission from the wifi provider?
Ever used an alias when registering on a website, like on this forum?
Ever post a pic that you didn't personally take or get permission to post from the owner of that pic?
Ever play cards, or golf, or shoot some billiards for some money (illegal in many places)?
The list goes on and on...
These days it's a very rare man who is not a criminal.