If you area as citizen you will not have aproblem re-entering the US. As for entering South America I suggest you call their Embassy. If the ACD is still open that means it has not been dismissed and some countries don't let people in with open cases. I have had clients get turned away by Canada with open cases.
I am a former federal and State prosecutor and now handle criminal defense and personal injury/civil rights cases. Feel free to check out my web site and contact me at (212) 577-9797 or via email at Eric@RothsteinLawNY.com. I was named to the Super Lawyers list as one of the top attorneys in New York for 2012. No more than 5 percent of the lawyers in the state are selected by Super Lawyers. The above answer is for informational purposes only and not meant as legal advice.
It should not be an issue
Joseph A. Lo Piccolo, Esq.
Immediate Past President, Criminal Courts Bar Association 11'-12'
Hession Bekoff & Lo Piccolo
1103 Stewart Ave, Suite 200
Garden City, NY 11530
516-408-3666 (o) / 516-408-3833 (f)
I am a criminal defense attorney practicing in Nassau, Suffolk and New York City. The above information is not a substitution for a meeting whereas all potential legal issues can be discussed.
Should be okay, but double check with an immigration attorney.
For further information you should see an attorney and discuss the matter completely. If you are in the New York City area, then you can reach me during normal business hours at 718 329 9500 or www.mynewyorkcitylawyer.com