Not now. Only in a massive war do we need the draft, like WWII. Selective Service works just fine now.
it's not fine to threaten young men with imprisonment for not signing up for something
You don't go to prison anymore for not signing up.
This is what they are legally empowered to do to you: "A man who fails to register may, if prosecuted and convicted, face a fine of up to $250,000 and/or a prison term of up to five years. "
http://www.sss.gov/FSbenefits.htm
They signed me up for it without me even submitting anything to them. I discovered that after I realized that I was past the date you are suppose to register by once you turn 18 and went to the site to register and discovered that my name had already been registered.
So i don't think one has much to worry about in the way of prison or fines if they register you without your knowledge.
Also to answer the topic question of course not the draft should never be reinstated.